1 /*
2 * Copyright (c) 2018, 2025, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 *
23 */
24
25 #include "cds/aotCacheAccess.hpp"
26 #include "cds/aotArtifactFinder.hpp"
27 #include "cds/aotClassInitializer.hpp"
28 #include "cds/aotClassLocation.hpp"
29 #include "cds/aotLogging.hpp"
30 #include "cds/aotReferenceObjSupport.hpp"
31 #include "cds/archiveBuilder.hpp"
32 #include "cds/archiveHeapLoader.hpp"
33 #include "cds/archiveHeapWriter.hpp"
34 #include "cds/archiveUtils.hpp"
35 #include "cds/cdsConfig.hpp"
36 #include "cds/cdsEnumKlass.hpp"
37 #include "cds/cdsHeapVerifier.hpp"
38 #include "cds/heapShared.hpp"
39 #include "cds/metaspaceShared.hpp"
40 #include "classfile/classLoaderData.hpp"
41 #include "classfile/classLoaderExt.hpp"
42 #include "classfile/javaClasses.inline.hpp"
43 #include "classfile/modules.hpp"
44 #include "classfile/stringTable.hpp"
45 #include "classfile/symbolTable.hpp"
46 #include "classfile/systemDictionary.hpp"
47 #include "classfile/systemDictionaryShared.hpp"
48 #include "classfile/vmClasses.hpp"
49 #include "classfile/vmSymbols.hpp"
50 #include "gc/shared/collectedHeap.hpp"
51 #include "gc/shared/gcLocker.hpp"
52 #include "gc/shared/gcVMOperations.hpp"
53 #include "logging/log.hpp"
54 #include "logging/logStream.hpp"
55 #include "memory/iterator.inline.hpp"
56 #include "memory/resourceArea.hpp"
57 #include "memory/universe.hpp"
58 #include "oops/compressedOops.inline.hpp"
59 #include "oops/fieldStreams.inline.hpp"
60 #include "oops/objArrayOop.inline.hpp"
61 #include "oops/oop.inline.hpp"
62 #include "oops/oopHandle.inline.hpp"
63 #include "oops/typeArrayOop.inline.hpp"
64 #include "prims/jvmtiExport.hpp"
65 #include "runtime/arguments.hpp"
66 #include "runtime/fieldDescriptor.inline.hpp"
67 #include "runtime/init.hpp"
68 #include "runtime/javaCalls.hpp"
69 #include "runtime/mutexLocker.hpp"
70 #include "runtime/safepointVerifiers.hpp"
71 #include "utilities/bitMap.inline.hpp"
72 #include "utilities/copy.hpp"
73 #if INCLUDE_G1GC
74 #include "gc/g1/g1CollectedHeap.hpp"
75 #endif
76
77 #if INCLUDE_CDS_JAVA_HEAP
78
79 struct ArchivableStaticFieldInfo {
80 const char* klass_name;
81 const char* field_name;
82 InstanceKlass* klass;
83 int offset;
84 BasicType type;
85
86 ArchivableStaticFieldInfo(const char* k, const char* f)
87 : klass_name(k), field_name(f), klass(nullptr), offset(0), type(T_ILLEGAL) {}
88
89 bool valid() {
90 return klass_name != nullptr;
91 }
92 };
93
94 class HeapShared::ContextMark : public StackObj {
95 ResourceMark rm;
96 public:
97 ContextMark(const char* c) : rm{} {
98 _context->push(c);
99 }
100 ~ContextMark() {
101 _context->pop();
102 }
103 };
104
105 DumpedInternedStrings *HeapShared::_dumped_interned_strings = nullptr;
106
107 size_t HeapShared::_alloc_count[HeapShared::ALLOC_STAT_SLOTS];
108 size_t HeapShared::_alloc_size[HeapShared::ALLOC_STAT_SLOTS];
109 size_t HeapShared::_total_obj_count;
110 size_t HeapShared::_total_obj_size;
111
112 #ifndef PRODUCT
113 #define ARCHIVE_TEST_FIELD_NAME "archivedObjects"
114 static Array<char>* _archived_ArchiveHeapTestClass = nullptr;
115 static const char* _test_class_name = nullptr;
116 static Klass* _test_class = nullptr;
117 static const ArchivedKlassSubGraphInfoRecord* _test_class_record = nullptr;
118 #endif
119
120
121 //
122 // If you add new entries to the following tables, you should know what you're doing!
123 //
124
125 static ArchivableStaticFieldInfo archive_subgraph_entry_fields[] = {
126 {"java/lang/Integer$IntegerCache", "archivedCache"},
127 {"java/lang/Long$LongCache", "archivedCache"},
128 {"java/lang/Byte$ByteCache", "archivedCache"},
129 {"java/lang/Short$ShortCache", "archivedCache"},
130 {"java/lang/Character$CharacterCache", "archivedCache"},
131 {"java/util/jar/Attributes$Name", "KNOWN_NAMES"},
132 {"sun/util/locale/BaseLocale", "constantBaseLocales"},
133 {"jdk/internal/module/ArchivedModuleGraph", "archivedModuleGraph"},
134 {"java/util/ImmutableCollections", "archivedObjects"},
135 {"java/lang/ModuleLayer", "EMPTY_LAYER"},
136 {"java/lang/module/Configuration", "EMPTY_CONFIGURATION"},
137 {"jdk/internal/math/FDBigInteger", "archivedCaches"},
138 {"java/lang/reflect/Proxy$ProxyBuilder", "archivedData"}, // FIXME -- requires AOTClassLinking
139
140 #ifndef PRODUCT
141 {nullptr, nullptr}, // Extra slot for -XX:ArchiveHeapTestClass
142 #endif
143 {nullptr, nullptr},
144 };
145
146 // full module graph
147 static ArchivableStaticFieldInfo fmg_archive_subgraph_entry_fields[] = {
148 {"jdk/internal/loader/ArchivedClassLoaders", "archivedClassLoaders"},
149 {ARCHIVED_BOOT_LAYER_CLASS, ARCHIVED_BOOT_LAYER_FIELD},
150 {"java/lang/Module$ArchivedData", "archivedData"},
151 {nullptr, nullptr},
152 };
153
154 KlassSubGraphInfo* HeapShared::_dump_time_special_subgraph;
155 ArchivedKlassSubGraphInfoRecord* HeapShared::_run_time_special_subgraph;
156 GrowableArrayCHeap<OopHandle, mtClassShared>* HeapShared::_pending_roots = nullptr;
157 GrowableArrayCHeap<const char*, mtClassShared>* HeapShared::_context = nullptr;
158 GrowableArrayCHeap<OopHandle, mtClassShared>* HeapShared::_root_segments = nullptr;
159 int HeapShared::_root_segment_max_size_elems;
160 OopHandle HeapShared::_scratch_basic_type_mirrors[T_VOID+1];
161 MetaspaceObjToOopHandleTable* HeapShared::_scratch_objects_table = nullptr;
162
163 static bool is_subgraph_root_class_of(ArchivableStaticFieldInfo fields[], InstanceKlass* ik) {
164 for (int i = 0; fields[i].valid(); i++) {
165 if (fields[i].klass == ik) {
166 return true;
167 }
168 }
169 return false;
170 }
171
172 bool HeapShared::is_subgraph_root_class(InstanceKlass* ik) {
173 return is_subgraph_root_class_of(archive_subgraph_entry_fields, ik) ||
174 is_subgraph_root_class_of(fmg_archive_subgraph_entry_fields, ik);
175 }
176
177 oop HeapShared::CachedOopInfo::orig_referrer() const {
178 return _orig_referrer.resolve();
179 }
180
181 void HeapShared::rehash_archived_object_cache() {
182 if (!CDSConfig::is_dumping_heap()) {
183 return;
184 }
185 assert(SafepointSynchronize::is_at_safepoint() ||
186 JavaThread::current()->is_in_no_safepoint_scope(), "sanity");
187
188 ArchivedObjectCache* new_cache =
189 new (mtClass)ArchivedObjectCache(archived_object_cache()->table_size(), MAX_TABLE_SIZE);
190
191 archived_object_cache()->iterate_all([&](OopHandle o, CachedOopInfo& info) {
192 new_cache->put_when_absent(o, info);
193 });
194
195 delete _archived_object_cache;
196 _archived_object_cache = new_cache;
197 }
198
199 unsigned HeapShared::oop_hash(oop const& p) {
200 assert(SafepointSynchronize::is_at_safepoint() ||
201 JavaThread::current()->is_in_no_safepoint_scope(), "sanity");
202 // Do not call p->identity_hash() as that will update the
203 // object header.
204 return primitive_hash(cast_from_oop<intptr_t>(p));
205 }
206
207 unsigned int HeapShared::oop_handle_hash_raw(const OopHandle& oh) {
208 return oop_hash(oh.resolve());
209 }
210
211 unsigned int HeapShared::oop_handle_hash(const OopHandle& oh) {
212 oop o = oh.resolve();
213 if (o == nullptr) {
214 return 0;
215 } else {
216 return o->identity_hash();
217 }
218 }
219
220 bool HeapShared::oop_handle_equals(const OopHandle& a, const OopHandle& b) {
221 return a.resolve() == b.resolve();
222 }
223
224 static void reset_states(oop obj, TRAPS) {
225 Handle h_obj(THREAD, obj);
226 InstanceKlass* klass = InstanceKlass::cast(obj->klass());
227 TempNewSymbol method_name = SymbolTable::new_symbol("resetArchivedStates");
228 Symbol* method_sig = vmSymbols::void_method_signature();
229
230 while (klass != nullptr) {
231 Method* method = klass->find_method(method_name, method_sig);
232 if (method != nullptr) {
233 assert(method->is_private(), "must be");
234 if (log_is_enabled(Debug, aot)) {
235 ResourceMark rm(THREAD);
236 log_debug(aot)(" calling %s", method->name_and_sig_as_C_string());
237 }
238 JavaValue result(T_VOID);
239 JavaCalls::call_special(&result, h_obj, klass,
240 method_name, method_sig, CHECK);
241 }
242 klass = klass->java_super();
243 }
244 }
245
246 void HeapShared::reset_archived_object_states(TRAPS) {
247 assert(CDSConfig::is_dumping_heap(), "dump-time only");
248 log_debug(aot)("Resetting platform loader");
249 reset_states(SystemDictionary::java_platform_loader(), CHECK);
250 log_debug(aot)("Resetting system loader");
251 reset_states(SystemDictionary::java_system_loader(), CHECK);
252
253 // Clean up jdk.internal.loader.ClassLoaders::bootLoader(), which is not
254 // directly used for class loading, but rather is used by the core library
255 // to keep track of resources, etc, loaded by the null class loader.
256 //
257 // Note, this object is non-null, and is not the same as
258 // ClassLoaderData::the_null_class_loader_data()->class_loader(),
259 // which is null.
260 log_debug(aot)("Resetting boot loader");
261 JavaValue result(T_OBJECT);
262 JavaCalls::call_static(&result,
263 vmClasses::jdk_internal_loader_ClassLoaders_klass(),
264 vmSymbols::bootLoader_name(),
265 vmSymbols::void_BuiltinClassLoader_signature(),
266 CHECK);
267 Handle boot_loader(THREAD, result.get_oop());
268 reset_states(boot_loader(), CHECK);
269 }
270
271 HeapShared::ArchivedObjectCache* HeapShared::_archived_object_cache = nullptr;
272
273 bool HeapShared::has_been_archived(oop obj) {
274 assert(CDSConfig::is_dumping_heap(), "dump-time only");
275 OopHandle oh(&obj);
276 return archived_object_cache()->get(oh) != nullptr;
277 }
278
279 int HeapShared::append_root(oop obj) {
280 assert(CDSConfig::is_dumping_heap(), "dump-time only");
281 if (obj != nullptr) {
282 assert(has_been_archived(obj), "must be");
283 }
284 // No GC should happen since we aren't scanning _pending_roots.
285 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
286
287 OopHandle oh(Universe::vm_global(), obj);
288 return _pending_roots->append(oh);
289 }
290
291 objArrayOop HeapShared::root_segment(int segment_idx) {
292 if (CDSConfig::is_dumping_heap() && !CDSConfig::is_dumping_final_static_archive()) {
293 assert(Thread::current() == (Thread*)VMThread::vm_thread(), "should be in vm thread");
294 } else {
295 assert(CDSConfig::is_using_archive(), "must be");
296 }
297
298 objArrayOop segment = (objArrayOop)_root_segments->at(segment_idx).resolve();
299 assert(segment != nullptr, "should have been initialized");
300 return segment;
301 }
302
303 class OrigToScratchObjectTable: public ResourceHashtable<OopHandle, OopHandle,
304 36137, // prime number
305 AnyObj::C_HEAP,
306 mtClassShared,
307 HeapShared::oop_handle_hash,
308 HeapShared::oop_handle_equals> {};
309
310 static OrigToScratchObjectTable* _orig_to_scratch_object_table = nullptr;
311
312 void HeapShared::track_scratch_object(oop orig_obj, oop scratch_obj) {
313 MutexLocker ml(ArchivedObjectTables_lock, Mutex::_no_safepoint_check_flag);
314 if (_orig_to_scratch_object_table == nullptr) {
315 _orig_to_scratch_object_table = new (mtClass)OrigToScratchObjectTable();
316 }
317
318 OopHandle orig_h(Universe::vm_global(), orig_obj);
319 OopHandle scratch_h(Universe::vm_global(), scratch_obj);
320 _orig_to_scratch_object_table->put_when_absent(orig_h, scratch_h);
321 }
322
323 oop HeapShared::orig_to_scratch_object(oop orig_obj) {
324 MutexLocker ml(ArchivedObjectTables_lock, Mutex::_no_safepoint_check_flag);
325 if (_orig_to_scratch_object_table != nullptr) {
326 OopHandle orig(&orig_obj);
327 OopHandle* v = _orig_to_scratch_object_table->get(orig);
328 if (v != nullptr) {
329 return v->resolve();
330 }
331 }
332 return nullptr;
333 }
334
335 // Permanent oops are used to support AOT-compiled methods, which may have in-line references
336 // to Strings and MH oops.
337 //
338 // At runtime, these oops are stored in _runtime_permanent_oops (which keeps them alive forever)
339 // and are accssed vis AOTCacheAccess::get_archived_object(int).
340 struct PermanentOopInfo {
341 int _index; // Gets assigned only if HeapShared::get_archived_object_permanent_index() has been called on the object
342 int _heap_offset; // Offset of the object from the bottom of the archived heap.
343 PermanentOopInfo(int index, int heap_offset) : _index(index), _heap_offset(heap_offset) {}
344 };
345
346 class PermanentOopTable: public ResourceHashtable<OopHandle, PermanentOopInfo,
347 36137, // prime number
348 AnyObj::C_HEAP,
349 mtClassShared,
350 HeapShared::oop_handle_hash,
351 HeapShared::oop_handle_equals> {};
352
353 static int _dumptime_permanent_oop_count = 0;
354 static PermanentOopTable* _dumptime_permanent_oop_table = nullptr;
355 static GrowableArrayCHeap<OopHandle, mtClassShared>* _runtime_permanent_oops = nullptr;
356
357 // ArchiveHeapWriter adds each archived heap object to _dumptime_permanent_oop_table,
358 // so we can remember their offset (from the bottom of the archived heap).
359 void HeapShared::add_to_permanent_oop_table(oop obj, int offset) {
360 assert_at_safepoint();
361 if (_dumptime_permanent_oop_table == nullptr) {
362 _dumptime_permanent_oop_table = new (mtClass)PermanentOopTable();
363 }
364
365 PermanentOopInfo info(-1, offset);
366 OopHandle oh(Universe::vm_global(), obj);
367 _dumptime_permanent_oop_table->put_when_absent(oh, info);
368 }
369
370 // A permanent index is assigned to an archived object ONLY when
371 // the AOT compiler calls this function.
372 int HeapShared::get_archived_object_permanent_index(oop obj) {
373 MutexLocker ml(ArchivedObjectTables_lock, Mutex::_no_safepoint_check_flag);
374
375 if (!CDSConfig::is_dumping_heap()) {
376 return -1; // Called by the Leyden old workflow
377 }
378 if (_dumptime_permanent_oop_table == nullptr) {
379 return -1;
380 }
381
382 if (_orig_to_scratch_object_table != nullptr) {
383 OopHandle orig(&obj);
384 OopHandle* v = _orig_to_scratch_object_table->get(orig);
385 if (v != nullptr) {
386 obj = v->resolve();
387 }
388 }
389
390 OopHandle tmp(&obj);
391 PermanentOopInfo* info = _dumptime_permanent_oop_table->get(tmp);
392 if (info == nullptr) {
393 return -1;
394 } else {
395 if (info->_index < 0) {
396 info->_index = _dumptime_permanent_oop_count++;
397 }
398 return info->_index;
399 }
400 }
401
402 oop HeapShared::get_archived_object(int permanent_index) {
403 assert(permanent_index >= 0, "sanity");
404 assert(ArchiveHeapLoader::is_in_use(), "sanity");
405 assert(_runtime_permanent_oops != nullptr, "sanity");
406
407 return _runtime_permanent_oops->at(permanent_index).resolve();
408 }
409
410 // Remember all archived heap objects that have a permanent index.
411 // table[i] = offset of oop whose permanent index is i.
412 void CachedCodeDirectoryInternal::dumptime_init_internal() {
413 const int count = _dumptime_permanent_oop_count;
414 if (count == 0) {
415 // Avoid confusing CDS code with zero-sized tables, just return.
416 log_info(cds)("No permanent oops");
417 _permanent_oop_count = count;
418 _permanent_oop_offsets = nullptr;
419 return;
420 }
421
422 int* table = (int*)AOTCacheAccess::allocate_aot_code_region(count * sizeof(int));
423 for (int i = 0; i < count; i++) {
424 table[count] = -1;
425 }
426 _dumptime_permanent_oop_table->iterate([&](OopHandle o, PermanentOopInfo& info) {
427 int index = info._index;
428 if (index >= 0) {
429 assert(index < count, "sanity");
430 table[index] = info._heap_offset;
431 }
432 return true; // continue
433 });
434
435 for (int i = 0; i < count; i++) {
436 assert(table[i] >= 0, "must be");
437 }
438
439 log_info(cds)("Dumped %d permanent oops", count);
440
441 _permanent_oop_count = count;
442 AOTCacheAccess::set_pointer(&_permanent_oop_offsets, table);
443 }
444
445 // This is called during the bootstrap of the production run, before any GC can happen.
446 // Record each permanent oop in a OopHandle for GC safety.
447 void CachedCodeDirectoryInternal::runtime_init_internal() {
448 int count = _permanent_oop_count;
449 int* table = _permanent_oop_offsets;
450 _runtime_permanent_oops = new GrowableArrayCHeap<OopHandle, mtClassShared>();
451 for (int i = 0; i < count; i++) {
452 oop obj = ArchiveHeapLoader::oop_from_offset(table[i]);
453 OopHandle oh(Universe::vm_global(), obj);
454 _runtime_permanent_oops->append(oh);
455 }
456 };
457
458 void HeapShared::get_segment_indexes(int idx, int& seg_idx, int& int_idx) {
459 assert(_root_segment_max_size_elems > 0, "sanity");
460
461 // Try to avoid divisions for the common case.
462 if (idx < _root_segment_max_size_elems) {
463 seg_idx = 0;
464 int_idx = idx;
465 } else {
466 seg_idx = idx / _root_segment_max_size_elems;
467 int_idx = idx % _root_segment_max_size_elems;
468 }
469
470 assert(idx == seg_idx * _root_segment_max_size_elems + int_idx,
471 "sanity: %d index maps to %d segment and %d internal", idx, seg_idx, int_idx);
472 }
473
474 // Returns an objArray that contains all the roots of the archived objects
475 oop HeapShared::get_root(int index, bool clear) {
476 assert(index >= 0, "sanity");
477 assert(!CDSConfig::is_dumping_heap() && CDSConfig::is_using_archive(), "runtime only");
478 assert(!_root_segments->is_empty(), "must have loaded shared heap");
479 int seg_idx, int_idx;
480 get_segment_indexes(index, seg_idx, int_idx);
481 oop result = root_segment(seg_idx)->obj_at(int_idx);
482 if (clear) {
483 clear_root(index);
484 }
485 return result;
486 }
487
488 void HeapShared::clear_root(int index) {
489 assert(index >= 0, "sanity");
490 assert(CDSConfig::is_using_archive(), "must be");
491 if (ArchiveHeapLoader::is_in_use()) {
492 int seg_idx, int_idx;
493 get_segment_indexes(index, seg_idx, int_idx);
494 if (log_is_enabled(Debug, aot, heap)) {
495 oop old = root_segment(seg_idx)->obj_at(int_idx);
496 log_debug(aot, heap)("Clearing root %d: was " PTR_FORMAT, index, p2i(old));
497 }
498 root_segment(seg_idx)->obj_at_put(int_idx, nullptr);
499 }
500 }
501
502 bool HeapShared::archive_object(oop obj, oop referrer, KlassSubGraphInfo* subgraph_info) {
503 assert(CDSConfig::is_dumping_heap(), "dump-time only");
504
505 assert(!obj->is_stackChunk(), "do not archive stack chunks");
506 if (has_been_archived(obj)) {
507 return true;
508 }
509
510 if (ArchiveHeapWriter::is_too_large_to_archive(obj->size())) {
511 log_debug(aot, heap)("Cannot archive, object (" PTR_FORMAT ") is too large: %zu",
512 p2i(obj), obj->size());
513 debug_trace();
514 return false;
515 } else {
516 count_allocation(obj->size());
517 ArchiveHeapWriter::add_source_obj(obj);
518 CachedOopInfo info = make_cached_oop_info(obj, referrer);
519
520 OopHandle oh(Universe::vm_global(), obj);
521 archived_object_cache()->put_when_absent(oh, info);
522 archived_object_cache()->maybe_grow();
523 mark_native_pointers(obj);
524
525 Klass* k = obj->klass();
526 if (k->is_instance_klass()) {
527 // Whenever we see a non-array Java object of type X, we mark X to be aot-initialized.
528 // This ensures that during the production run, whenever Java code sees a cached object
529 // of type X, we know that X is already initialized. (see TODO comment below ...)
530
531 if (InstanceKlass::cast(k)->is_enum_subclass()
532 // We can't rerun <clinit> of enum classes (see cdsEnumKlass.cpp) so
533 // we must store them as AOT-initialized.
534 || (subgraph_info == _dump_time_special_subgraph))
535 // TODO: we do this only for the special subgraph for now. Extending this to
536 // other subgraphs would require more refactoring of the core library (such as
537 // move some initialization logic into runtimeSetup()).
538 //
539 // For the other subgraphs, we have a weaker mechanism to ensure that
540 // all classes in a subgraph are initialized before the subgraph is programmatically
541 // returned from jdk.internal.misc.CDS::initializeFromArchive().
542 // See HeapShared::initialize_from_archived_subgraph().
543 {
544 AOTArtifactFinder::add_aot_inited_class(InstanceKlass::cast(k));
545 }
546
547 if (java_lang_Class::is_instance(obj)) {
548 Klass* mirror_k = java_lang_Class::as_Klass(obj);
549 if (mirror_k != nullptr) {
550 AOTArtifactFinder::add_cached_class(mirror_k);
551 }
552 } else if (java_lang_invoke_ResolvedMethodName::is_instance(obj)) {
553 Method* m = java_lang_invoke_ResolvedMethodName::vmtarget(obj);
554 if (m != nullptr) {
555 InstanceKlass* method_holder = m->method_holder();
556 AOTArtifactFinder::add_cached_class(method_holder);
557 }
558 }
559 }
560
561 if (log_is_enabled(Debug, aot, heap)) {
562 ResourceMark rm;
563 LogTarget(Debug, aot, heap) log;
564 LogStream out(log);
565 out.print("Archived heap object " PTR_FORMAT " : %s ",
566 p2i(obj), obj->klass()->external_name());
567 if (java_lang_Class::is_instance(obj)) {
568 Klass* k = java_lang_Class::as_Klass(obj);
569 if (k != nullptr) {
570 out.print("%s", k->external_name());
571 } else {
572 out.print("primitive");
573 }
574 }
575 out.cr();
576 }
577
578 return true;
579 }
580 }
581
582 class MetaspaceObjToOopHandleTable: public ResourceHashtable<MetaspaceObj*, OopHandle,
583 36137, // prime number
584 AnyObj::C_HEAP,
585 mtClassShared> {
586 public:
587 oop get_oop(MetaspaceObj* ptr) {
588 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
589 OopHandle* handle = get(ptr);
590 if (handle != nullptr) {
591 return handle->resolve();
592 } else {
593 return nullptr;
594 }
595 }
596 void set_oop(MetaspaceObj* ptr, oop o) {
597 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
598 OopHandle handle(Universe::vm_global(), o);
599 bool is_new = put(ptr, handle);
600 assert(is_new, "cannot set twice");
601 }
602 void remove_oop(MetaspaceObj* ptr) {
603 MutexLocker ml(ScratchObjects_lock, Mutex::_no_safepoint_check_flag);
604 OopHandle* handle = get(ptr);
605 if (handle != nullptr) {
606 handle->release(Universe::vm_global());
607 remove(ptr);
608 }
609 }
610 };
611
612 void HeapShared::add_scratch_resolved_references(ConstantPool* src, objArrayOop dest) {
613 if (SystemDictionaryShared::is_builtin_loader(src->pool_holder()->class_loader_data())) {
614 _scratch_objects_table->set_oop(src, dest);
615 }
616 }
617
618 objArrayOop HeapShared::scratch_resolved_references(ConstantPool* src) {
619 return (objArrayOop)_scratch_objects_table->get_oop(src);
620 }
621
622 void HeapShared::init_dumping() {
623 _scratch_objects_table = new (mtClass)MetaspaceObjToOopHandleTable();
624 _pending_roots = new GrowableArrayCHeap<OopHandle, mtClassShared>(500);
625 }
626
627 void HeapShared::init_scratch_objects_for_basic_type_mirrors(TRAPS) {
628 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
629 BasicType bt = (BasicType)i;
630 if (!is_reference_type(bt)) {
631 oop m = java_lang_Class::create_basic_type_mirror(type2name(bt), bt, CHECK);
632 _scratch_basic_type_mirrors[i] = OopHandle(Universe::vm_global(), m);
633 track_scratch_object(Universe::java_mirror(bt), m);
634 }
635 }
636 }
637
638 // Given java_mirror that represents a (primitive or reference) type T,
639 // return the "scratch" version that represents the same type T.
640 // Note that if java_mirror will be returned if it's already a
641 // scratch mirror.
642 //
643 // See java_lang_Class::create_scratch_mirror() for more info.
644 oop HeapShared::scratch_java_mirror(oop java_mirror) {
645 assert(java_lang_Class::is_instance(java_mirror), "must be");
646
647 for (int i = T_BOOLEAN; i < T_VOID+1; i++) {
648 BasicType bt = (BasicType)i;
649 if (!is_reference_type(bt)) {
650 if (_scratch_basic_type_mirrors[i].resolve() == java_mirror) {
651 return java_mirror;
652 }
653 }
654 }
655
656 if (java_lang_Class::is_primitive(java_mirror)) {
657 return scratch_java_mirror(java_lang_Class::as_BasicType(java_mirror));
658 } else {
659 return scratch_java_mirror(java_lang_Class::as_Klass(java_mirror));
660 }
661 }
662
663 oop HeapShared::scratch_java_mirror(BasicType t) {
664 assert((uint)t < T_VOID+1, "range check");
665 assert(!is_reference_type(t), "sanity");
666 return _scratch_basic_type_mirrors[t].resolve();
667 }
668
669 oop HeapShared::scratch_java_mirror(Klass* k) {
670 return _scratch_objects_table->get_oop(k);
671 }
672
673 void HeapShared::set_scratch_java_mirror(Klass* k, oop mirror) {
674 track_scratch_object(k->java_mirror(), mirror);
675 _scratch_objects_table->set_oop(k, mirror);
676 }
677
678 void HeapShared::remove_scratch_objects(Klass* k) {
679 // Klass is being deallocated. Java mirror can still be alive, and it should not
680 // point to dead klass. We need to break the link from mirror to the Klass.
681 // See how InstanceKlass::deallocate_contents does it for normal mirrors.
682 oop mirror = _scratch_objects_table->get_oop(k);
683 if (mirror != nullptr) {
684 java_lang_Class::set_klass(mirror, nullptr);
685 }
686 _scratch_objects_table->remove_oop(k);
687 if (k->is_instance_klass()) {
688 _scratch_objects_table->remove(InstanceKlass::cast(k)->constants());
689 }
690 if (mirror != nullptr) {
691 OopHandle tmp(&mirror);
692 OopHandle* v = _orig_to_scratch_object_table->get(tmp);
693 if (v != nullptr) {
694 oop scratch_mirror = v->resolve();
695 java_lang_Class::set_klass(scratch_mirror, nullptr);
696 _orig_to_scratch_object_table->remove(tmp);
697 }
698 }
699 }
700
701 //TODO: we eventually want a more direct test for these kinds of things.
702 //For example the JVM could record some bit of context from the creation
703 //of the klass, such as who called the hidden class factory. Using
704 //string compares on names is fragile and will break as soon as somebody
705 //changes the names in the JDK code. See discussion in JDK-8342481 for
706 //related ideas about marking AOT-related classes.
707 bool HeapShared::is_lambda_form_klass(InstanceKlass* ik) {
708 return ik->is_hidden() &&
709 (ik->name()->starts_with("java/lang/invoke/LambdaForm$MH+") ||
710 ik->name()->starts_with("java/lang/invoke/LambdaForm$DMH+") ||
711 ik->name()->starts_with("java/lang/invoke/LambdaForm$BMH+") ||
712 ik->name()->starts_with("java/lang/invoke/LambdaForm$VH+"));
713 }
714
715 bool HeapShared::is_lambda_proxy_klass(InstanceKlass* ik) {
716 return ik->is_hidden() && (ik->name()->index_of_at(0, "$$Lambda+", 9) > 0);
717 }
718
719 bool HeapShared::is_string_concat_klass(InstanceKlass* ik) {
720 return ik->is_hidden() && ik->name()->starts_with("java/lang/String$$StringConcat");
721 }
722
723 bool HeapShared::is_archivable_hidden_klass(InstanceKlass* ik) {
724 return CDSConfig::is_dumping_method_handles() &&
725 (is_lambda_form_klass(ik) || is_lambda_proxy_klass(ik) || is_string_concat_klass(ik));
726 }
727
728
729 void HeapShared::copy_and_rescan_aot_inited_mirror(InstanceKlass* ik) {
730 ik->set_has_aot_initialized_mirror();
731 if (AOTClassInitializer::is_runtime_setup_required(ik)) {
732 ik->set_is_runtime_setup_required();
733 }
734
735 oop orig_mirror = ik->java_mirror();
736 oop m = scratch_java_mirror(ik);
737 assert(ik->is_initialized(), "must be");
738
739 int nfields = 0;
740 for (JavaFieldStream fs(ik); !fs.done(); fs.next()) {
741 if (fs.access_flags().is_static()) {
742 fieldDescriptor& fd = fs.field_descriptor();
743 int offset = fd.offset();
744 switch (fd.field_type()) {
745 case T_OBJECT:
746 case T_ARRAY:
747 {
748 oop field_obj = orig_mirror->obj_field(offset);
749 if (offset == java_lang_Class::reflection_data_offset()) {
750 // Class::reflectData use SoftReference, which cannot be archived. Set it
751 // to null and it will be recreated at runtime.
752 field_obj = nullptr;
753 }
754 m->obj_field_put(offset, field_obj);
755 if (field_obj != nullptr) {
756 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, field_obj);
757 assert(success, "sanity");
758 }
759 }
760 break;
761 case T_BOOLEAN:
762 m->bool_field_put(offset, orig_mirror->bool_field(offset));
763 break;
764 case T_BYTE:
765 m->byte_field_put(offset, orig_mirror->byte_field(offset));
766 break;
767 case T_SHORT:
768 m->short_field_put(offset, orig_mirror->short_field(offset));
769 break;
770 case T_CHAR:
771 m->char_field_put(offset, orig_mirror->char_field(offset));
772 break;
773 case T_INT:
774 m->int_field_put(offset, orig_mirror->int_field(offset));
775 break;
776 case T_LONG:
777 m->long_field_put(offset, orig_mirror->long_field(offset));
778 break;
779 case T_FLOAT:
780 m->float_field_put(offset, orig_mirror->float_field(offset));
781 break;
782 case T_DOUBLE:
783 m->double_field_put(offset, orig_mirror->double_field(offset));
784 break;
785 default:
786 ShouldNotReachHere();
787 }
788 nfields ++;
789 }
790 }
791
792 oop class_data = java_lang_Class::class_data(orig_mirror);
793 java_lang_Class::set_class_data(m, class_data);
794 if (class_data != nullptr) {
795 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, class_data);
796 assert(success, "sanity");
797 }
798
799 if (log_is_enabled(Debug, aot, init)) {
800 ResourceMark rm;
801 log_debug(aot, init)("copied %3d field(s) in aot-initialized mirror %s%s%s", nfields, ik->external_name(),
802 ik->is_hidden() ? " (hidden)" : "",
803 ik->is_enum_subclass() ? " (enum)" : "");
804 }
805 }
806
807 static void copy_java_mirror_hashcode(oop orig_mirror, oop scratch_m) {
808 // We need to retain the identity_hash, because it may have been used by some hashtables
809 // in the shared heap.
810 if (!orig_mirror->fast_no_hash_check()) {
811 intptr_t src_hash = orig_mirror->identity_hash();
812 if (UseCompactObjectHeaders) {
813 narrowKlass nk = CompressedKlassPointers::encode(orig_mirror->klass());
814 scratch_m->set_mark(markWord::prototype().set_narrow_klass(nk).copy_set_hash(src_hash));
815 } else {
816 scratch_m->set_mark(markWord::prototype().copy_set_hash(src_hash));
817 }
818 assert(scratch_m->mark().is_unlocked(), "sanity");
819
820 DEBUG_ONLY(intptr_t archived_hash = scratch_m->identity_hash());
821 assert(src_hash == archived_hash, "Different hash codes: original " INTPTR_FORMAT ", archived " INTPTR_FORMAT, src_hash, archived_hash);
822 }
823 }
824
825 static objArrayOop get_archived_resolved_references(InstanceKlass* src_ik) {
826 if (SystemDictionaryShared::is_builtin_loader(src_ik->class_loader_data())) {
827 objArrayOop rr = src_ik->constants()->resolved_references_or_null();
828 if (rr != nullptr && !ArchiveHeapWriter::is_too_large_to_archive(rr)) {
829 return HeapShared::scratch_resolved_references(src_ik->constants());
830 }
831 }
832 return nullptr;
833 }
834
835 void HeapShared::archive_strings() {
836 oop shared_strings_array = StringTable::init_shared_strings_array();
837 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, shared_strings_array);
838 assert(success, "shared strings array must not point to arrays or strings that are too large to archive");
839 StringTable::set_shared_strings_array_index(append_root(shared_strings_array));
840 }
841
842 int HeapShared::archive_exception_instance(oop exception) {
843 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, exception);
844 assert(success, "sanity");
845 return append_root(exception);
846 }
847
848 void HeapShared::mark_native_pointers(oop orig_obj) {
849 if (java_lang_Class::is_instance(orig_obj)) {
850 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::klass_offset());
851 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_Class::array_klass_offset());
852 } else if (java_lang_invoke_ResolvedMethodName::is_instance(orig_obj)) {
853 ArchiveHeapWriter::mark_native_pointer(orig_obj, java_lang_invoke_ResolvedMethodName::vmtarget_offset());
854 }
855 }
856
857 void HeapShared::get_pointer_info(oop src_obj, bool& has_oop_pointers, bool& has_native_pointers) {
858 OopHandle oh(&src_obj);
859 CachedOopInfo* info = archived_object_cache()->get(oh);
860 assert(info != nullptr, "must be");
861 has_oop_pointers = info->has_oop_pointers();
862 has_native_pointers = info->has_native_pointers();
863 }
864
865 void HeapShared::set_has_native_pointers(oop src_obj) {
866 OopHandle oh(&src_obj);
867 CachedOopInfo* info = archived_object_cache()->get(oh);
868 assert(info != nullptr, "must be");
869 info->set_has_native_pointers();
870 }
871
872 // Between start_scanning_for_oops() and end_scanning_for_oops(), we discover all Java heap objects that
873 // should be stored in the AOT cache. The scanning is coordinated by AOTArtifactFinder.
874 void HeapShared::start_scanning_for_oops() {
875 {
876 NoSafepointVerifier nsv;
877
878 // The special subgraph doesn't belong to any class. We use Object_klass() here just
879 // for convenience.
880 _dump_time_special_subgraph = init_subgraph_info(vmClasses::Object_klass(), false);
881 _context = new GrowableArrayCHeap<const char*, mtClassShared>(250);
882
883 // Cache for recording where the archived objects are copied to
884 create_archived_object_cache();
885
886 if (UseCompressedOops || UseG1GC) {
887 aot_log_info(aot)("Heap range = [" PTR_FORMAT " - " PTR_FORMAT "]",
888 UseCompressedOops ? p2i(CompressedOops::begin()) :
889 p2i((address)G1CollectedHeap::heap()->reserved().start()),
890 UseCompressedOops ? p2i(CompressedOops::end()) :
891 p2i((address)G1CollectedHeap::heap()->reserved().end()));
892 }
893
894 archive_subgraphs();
895 }
896
897 init_seen_objects_table();
898 Universe::archive_exception_instances();
899 }
900
901 void HeapShared::end_scanning_for_oops() {
902 archive_strings();
903 delete_seen_objects_table();
904 }
905
906 void HeapShared::write_heap(ArchiveHeapInfo *heap_info) {
907 {
908 NoSafepointVerifier nsv;
909 if (!SkipArchiveHeapVerification) {
910 CDSHeapVerifier::verify();
911 }
912 check_special_subgraph_classes();
913 }
914
915 StringTable::write_shared_table();
916 GrowableArrayCHeap<oop, mtClassShared>* roots = new GrowableArrayCHeap<oop, mtClassShared>(_pending_roots->length());
917 for (int i = 0; i < _pending_roots->length(); i++) {
918 roots->append(_pending_roots->at(i).resolve());
919 }
920 ArchiveHeapWriter::write(roots, heap_info);
921 delete roots;
922
923 ArchiveBuilder::OtherROAllocMark mark;
924 write_subgraph_info_table();
925 }
926
927 void HeapShared::scan_java_mirror(oop orig_mirror) {
928 oop m = scratch_java_mirror(orig_mirror);
929 if (m != nullptr) { // nullptr if for custom class loader
930 copy_java_mirror_hashcode(orig_mirror, m);
931 bool success = archive_reachable_objects_from(1, _dump_time_special_subgraph, m);
932 assert(success, "sanity");
933 }
934 }
935
936 void HeapShared::scan_java_class(Klass* orig_k) {
937 scan_java_mirror(orig_k->java_mirror());
938
939 if (orig_k->is_instance_klass()) {
940 InstanceKlass* orig_ik = InstanceKlass::cast(orig_k);
941 orig_ik->constants()->prepare_resolved_references_for_archiving();
942 objArrayOop rr = get_archived_resolved_references(orig_ik);
943 if (rr != nullptr) {
944 bool success = HeapShared::archive_reachable_objects_from(1, _dump_time_special_subgraph, rr);
945 assert(success, "must be");
946 }
947 }
948 }
949
950 void HeapShared::archive_subgraphs() {
951 assert(CDSConfig::is_dumping_heap(), "must be");
952
953 archive_object_subgraphs(archive_subgraph_entry_fields,
954 false /* is_full_module_graph */);
955
956 if (CDSConfig::is_dumping_full_module_graph()) {
957 archive_object_subgraphs(fmg_archive_subgraph_entry_fields,
958 true /* is_full_module_graph */);
959 Modules::verify_archived_modules();
960 }
961 }
962
963 //
964 // Subgraph archiving support
965 //
966 HeapShared::DumpTimeKlassSubGraphInfoTable* HeapShared::_dump_time_subgraph_info_table = nullptr;
967 HeapShared::RunTimeKlassSubGraphInfoTable HeapShared::_run_time_subgraph_info_table;
968
969 // Get the subgraph_info for Klass k. A new subgraph_info is created if
970 // there is no existing one for k. The subgraph_info records the "buffered"
971 // address of the class.
972 KlassSubGraphInfo* HeapShared::init_subgraph_info(Klass* k, bool is_full_module_graph) {
973 assert(CDSConfig::is_dumping_heap(), "dump time only");
974 bool created;
975 KlassSubGraphInfo* info =
976 _dump_time_subgraph_info_table->put_if_absent(k, KlassSubGraphInfo(k, is_full_module_graph),
977 &created);
978 assert(created, "must not initialize twice");
979 return info;
980 }
981
982 KlassSubGraphInfo* HeapShared::get_subgraph_info(Klass* k) {
983 assert(CDSConfig::is_dumping_heap(), "dump time only");
984 KlassSubGraphInfo* info = _dump_time_subgraph_info_table->get(k);
985 assert(info != nullptr, "must have been initialized");
986 return info;
987 }
988
989 // Add an entry field to the current KlassSubGraphInfo.
990 void KlassSubGraphInfo::add_subgraph_entry_field(int static_field_offset, oop v) {
991 assert(CDSConfig::is_dumping_heap(), "dump time only");
992 if (_subgraph_entry_fields == nullptr) {
993 _subgraph_entry_fields =
994 new (mtClass) GrowableArray<int>(10, mtClass);
995 }
996 _subgraph_entry_fields->append(static_field_offset);
997 _subgraph_entry_fields->append(HeapShared::append_root(v));
998 }
999
1000 // Add the Klass* for an object in the current KlassSubGraphInfo's subgraphs.
1001 // Only objects of boot classes can be included in sub-graph.
1002 void KlassSubGraphInfo::add_subgraph_object_klass(Klass* orig_k) {
1003 assert(CDSConfig::is_dumping_heap(), "dump time only");
1004
1005 if (_subgraph_object_klasses == nullptr) {
1006 _subgraph_object_klasses =
1007 new (mtClass) GrowableArray<Klass*>(50, mtClass);
1008 }
1009
1010 if (_k == orig_k) {
1011 // Don't add the Klass containing the sub-graph to it's own klass
1012 // initialization list.
1013 return;
1014 }
1015
1016 if (orig_k->is_instance_klass()) {
1017 #ifdef ASSERT
1018 InstanceKlass* ik = InstanceKlass::cast(orig_k);
1019 if (CDSConfig::is_dumping_method_handles()) {
1020 // -XX:AOTInitTestClass must be used carefully in regression tests to
1021 // include only classes that are safe to aot-initialize.
1022 assert(ik->class_loader() == nullptr ||
1023 HeapShared::is_lambda_proxy_klass(ik) ||
1024 AOTClassInitializer::has_test_class(),
1025 "we can archive only instances of boot classes or lambda proxy classes");
1026 } else {
1027 assert(ik->class_loader() == nullptr, "must be boot class");
1028 }
1029 #endif
1030 // vmClasses::xxx_klass() are not updated, need to check
1031 // the original Klass*
1032 if (orig_k == vmClasses::String_klass() ||
1033 orig_k == vmClasses::Object_klass()) {
1034 // Initialized early during VM initialization. No need to be added
1035 // to the sub-graph object class list.
1036 return;
1037 }
1038 check_allowed_klass(InstanceKlass::cast(orig_k));
1039 } else if (orig_k->is_objArray_klass()) {
1040 Klass* abk = ObjArrayKlass::cast(orig_k)->bottom_klass();
1041 if (abk->is_instance_klass()) {
1042 assert(InstanceKlass::cast(abk)->defined_by_boot_loader(),
1043 "must be boot class");
1044 check_allowed_klass(InstanceKlass::cast(ObjArrayKlass::cast(orig_k)->bottom_klass()));
1045 }
1046 if (orig_k == Universe::objectArrayKlass()) {
1047 // Initialized early during Universe::genesis. No need to be added
1048 // to the list.
1049 return;
1050 }
1051 } else {
1052 assert(orig_k->is_typeArray_klass(), "must be");
1053 // Primitive type arrays are created early during Universe::genesis.
1054 return;
1055 }
1056
1057 if (log_is_enabled(Debug, aot, heap)) {
1058 if (!_subgraph_object_klasses->contains(orig_k)) {
1059 ResourceMark rm;
1060 log_debug(aot, heap)("Adding klass %s", orig_k->external_name());
1061 }
1062 }
1063
1064 _subgraph_object_klasses->append_if_missing(orig_k);
1065 _has_non_early_klasses |= is_non_early_klass(orig_k);
1066 }
1067
1068 void KlassSubGraphInfo::check_allowed_klass(InstanceKlass* ik) {
1069 #ifndef PRODUCT
1070 if (AOTClassInitializer::has_test_class()) {
1071 // The tests can cache arbitrary types of objects.
1072 return;
1073 }
1074 #endif
1075
1076 if (ik->module()->name() == vmSymbols::java_base()) {
1077 assert(ik->package() != nullptr, "classes in java.base cannot be in unnamed package");
1078 return;
1079 }
1080
1081 const char* lambda_msg = "";
1082 if (CDSConfig::is_dumping_method_handles()) {
1083 lambda_msg = ", or a lambda proxy class";
1084 if (HeapShared::is_lambda_proxy_klass(ik) &&
1085 (ik->class_loader() == nullptr ||
1086 ik->class_loader() == SystemDictionary::java_platform_loader() ||
1087 ik->class_loader() == SystemDictionary::java_system_loader())) {
1088 return;
1089 }
1090 }
1091
1092 #ifndef PRODUCT
1093 if (!ik->module()->is_named() && ik->package() == nullptr && ArchiveHeapTestClass != nullptr) {
1094 // This class is loaded by ArchiveHeapTestClass
1095 return;
1096 }
1097 const char* testcls_msg = ", or a test class in an unnamed package of an unnamed module";
1098 #else
1099 const char* testcls_msg = "";
1100 #endif
1101
1102 ResourceMark rm;
1103 log_error(aot, heap)("Class %s not allowed in archive heap. Must be in java.base%s%s",
1104 ik->external_name(), lambda_msg, testcls_msg);
1105 MetaspaceShared::unrecoverable_writing_error();
1106 }
1107
1108 bool KlassSubGraphInfo::is_non_early_klass(Klass* k) {
1109 if (k->is_objArray_klass()) {
1110 k = ObjArrayKlass::cast(k)->bottom_klass();
1111 }
1112 if (k->is_instance_klass()) {
1113 if (!SystemDictionaryShared::is_early_klass(InstanceKlass::cast(k))) {
1114 ResourceMark rm;
1115 log_info(aot, heap)("non-early: %s", k->external_name());
1116 return true;
1117 } else {
1118 return false;
1119 }
1120 } else {
1121 return false;
1122 }
1123 }
1124
1125 // Initialize an archived subgraph_info_record from the given KlassSubGraphInfo.
1126 void ArchivedKlassSubGraphInfoRecord::init(KlassSubGraphInfo* info) {
1127 _k = ArchiveBuilder::get_buffered_klass(info->klass());
1128 _entry_field_records = nullptr;
1129 _subgraph_object_klasses = nullptr;
1130 _is_full_module_graph = info->is_full_module_graph();
1131
1132 if (_is_full_module_graph) {
1133 // Consider all classes referenced by the full module graph as early -- we will be
1134 // allocating objects of these classes during JVMTI early phase, so they cannot
1135 // be processed by (non-early) JVMTI ClassFileLoadHook
1136 _has_non_early_klasses = false;
1137 } else {
1138 _has_non_early_klasses = info->has_non_early_klasses();
1139 }
1140
1141 if (_has_non_early_klasses) {
1142 ResourceMark rm;
1143 log_info(aot, heap)(
1144 "Subgraph of klass %s has non-early klasses and cannot be used when JVMTI ClassFileLoadHook is enabled",
1145 _k->external_name());
1146 }
1147
1148 // populate the entry fields
1149 GrowableArray<int>* entry_fields = info->subgraph_entry_fields();
1150 if (entry_fields != nullptr) {
1151 int num_entry_fields = entry_fields->length();
1152 assert(num_entry_fields % 2 == 0, "sanity");
1153 _entry_field_records =
1154 ArchiveBuilder::new_ro_array<int>(num_entry_fields);
1155 for (int i = 0 ; i < num_entry_fields; i++) {
1156 _entry_field_records->at_put(i, entry_fields->at(i));
1157 }
1158 }
1159
1160 // <recorded_klasses> has the Klasses of all the objects that are referenced by this subgraph.
1161 // Copy those that need to be explicitly initialized into <_subgraph_object_klasses>.
1162 GrowableArray<Klass*>* recorded_klasses = info->subgraph_object_klasses();
1163 if (recorded_klasses != nullptr) {
1164 // AOT-inited classes are automatically marked as "initialized" during bootstrap. When
1165 // programmatically loading a subgraph, we only need to explicitly initialize the classes
1166 // that are not aot-inited.
1167 int num_to_copy = 0;
1168 for (int i = 0; i < recorded_klasses->length(); i++) {
1169 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
1170 if (!subgraph_k->has_aot_initialized_mirror()) {
1171 num_to_copy ++;
1172 }
1173 }
1174
1175 _subgraph_object_klasses = ArchiveBuilder::new_ro_array<Klass*>(num_to_copy);
1176 bool is_special = (_k == ArchiveBuilder::get_buffered_klass(vmClasses::Object_klass()));
1177 for (int i = 0, n = 0; i < recorded_klasses->length(); i++) {
1178 Klass* subgraph_k = ArchiveBuilder::get_buffered_klass(recorded_klasses->at(i));
1179 if (subgraph_k->has_aot_initialized_mirror()) {
1180 continue;
1181 }
1182 if (log_is_enabled(Info, aot, heap)) {
1183 ResourceMark rm;
1184 const char* owner_name = is_special ? "<special>" : _k->external_name();
1185 if (subgraph_k->is_instance_klass()) {
1186 InstanceKlass* src_ik = InstanceKlass::cast(ArchiveBuilder::current()->get_source_addr(subgraph_k));
1187 }
1188 log_info(aot, heap)(
1189 "Archived object klass %s (%2d) => %s",
1190 owner_name, n, subgraph_k->external_name());
1191 }
1192 _subgraph_object_klasses->at_put(n, subgraph_k);
1193 ArchivePtrMarker::mark_pointer(_subgraph_object_klasses->adr_at(n));
1194 n++;
1195 }
1196 }
1197
1198 ArchivePtrMarker::mark_pointer(&_k);
1199 ArchivePtrMarker::mark_pointer(&_entry_field_records);
1200 ArchivePtrMarker::mark_pointer(&_subgraph_object_klasses);
1201 }
1202
1203 class HeapShared::CopyKlassSubGraphInfoToArchive : StackObj {
1204 CompactHashtableWriter* _writer;
1205 public:
1206 CopyKlassSubGraphInfoToArchive(CompactHashtableWriter* writer) : _writer(writer) {}
1207
1208 bool do_entry(Klass* klass, KlassSubGraphInfo& info) {
1209 if (info.subgraph_object_klasses() != nullptr || info.subgraph_entry_fields() != nullptr) {
1210 ArchivedKlassSubGraphInfoRecord* record = HeapShared::archive_subgraph_info(&info);
1211 Klass* buffered_k = ArchiveBuilder::get_buffered_klass(klass);
1212 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary((address)buffered_k);
1213 u4 delta = ArchiveBuilder::current()->any_to_offset_u4(record);
1214 _writer->add(hash, delta);
1215 }
1216 return true; // keep on iterating
1217 }
1218 };
1219
1220 ArchivedKlassSubGraphInfoRecord* HeapShared::archive_subgraph_info(KlassSubGraphInfo* info) {
1221 ArchivedKlassSubGraphInfoRecord* record =
1222 (ArchivedKlassSubGraphInfoRecord*)ArchiveBuilder::ro_region_alloc(sizeof(ArchivedKlassSubGraphInfoRecord));
1223 record->init(info);
1224 if (info == _dump_time_special_subgraph) {
1225 _run_time_special_subgraph = record;
1226 }
1227 return record;
1228 }
1229
1230 // Build the records of archived subgraph infos, which include:
1231 // - Entry points to all subgraphs from the containing class mirror. The entry
1232 // points are static fields in the mirror. For each entry point, the field
1233 // offset, and value are recorded in the sub-graph
1234 // info. The value is stored back to the corresponding field at runtime.
1235 // - A list of klasses that need to be loaded/initialized before archived
1236 // java object sub-graph can be accessed at runtime.
1237 void HeapShared::write_subgraph_info_table() {
1238 // Allocate the contents of the hashtable(s) inside the RO region of the CDS archive.
1239 DumpTimeKlassSubGraphInfoTable* d_table = _dump_time_subgraph_info_table;
1240 CompactHashtableStats stats;
1241
1242 _run_time_subgraph_info_table.reset();
1243
1244 CompactHashtableWriter writer(d_table->_count, &stats);
1245 CopyKlassSubGraphInfoToArchive copy(&writer);
1246 d_table->iterate(©);
1247 writer.dump(&_run_time_subgraph_info_table, "subgraphs");
1248
1249 #ifndef PRODUCT
1250 if (ArchiveHeapTestClass != nullptr) {
1251 size_t len = strlen(ArchiveHeapTestClass) + 1;
1252 Array<char>* array = ArchiveBuilder::new_ro_array<char>((int)len);
1253 strncpy(array->adr_at(0), ArchiveHeapTestClass, len);
1254 _archived_ArchiveHeapTestClass = array;
1255 }
1256 #endif
1257 if (log_is_enabled(Info, aot, heap)) {
1258 print_stats();
1259 }
1260 }
1261
1262 void HeapShared::add_root_segment(objArrayOop segment_oop) {
1263 assert(segment_oop != nullptr, "must be");
1264 assert(ArchiveHeapLoader::is_in_use(), "must be");
1265 if (_root_segments == nullptr) {
1266 _root_segments = new GrowableArrayCHeap<OopHandle, mtClassShared>(10);
1267 }
1268 _root_segments->push(OopHandle(Universe::vm_global(), segment_oop));
1269 }
1270
1271 void HeapShared::init_root_segment_sizes(int max_size_elems) {
1272 _root_segment_max_size_elems = max_size_elems;
1273 }
1274
1275 void HeapShared::serialize_tables(SerializeClosure* soc) {
1276
1277 #ifndef PRODUCT
1278 soc->do_ptr(&_archived_ArchiveHeapTestClass);
1279 if (soc->reading() && _archived_ArchiveHeapTestClass != nullptr) {
1280 _test_class_name = _archived_ArchiveHeapTestClass->adr_at(0);
1281 setup_test_class(_test_class_name);
1282 }
1283 #endif
1284
1285 _run_time_subgraph_info_table.serialize_header(soc);
1286 soc->do_ptr(&_run_time_special_subgraph);
1287 }
1288
1289 static void verify_the_heap(Klass* k, const char* which) {
1290 if (VerifyArchivedFields > 0) {
1291 ResourceMark rm;
1292 log_info(aot, heap)("Verify heap %s initializing static field(s) in %s",
1293 which, k->external_name());
1294
1295 VM_Verify verify_op;
1296 VMThread::execute(&verify_op);
1297
1298 if (VerifyArchivedFields > 1 && is_init_completed()) {
1299 // At this time, the oop->klass() of some archived objects in the heap may not
1300 // have been loaded into the system dictionary yet. Nevertheless, oop->klass() should
1301 // have enough information (object size, oop maps, etc) so that a GC can be safely
1302 // performed.
1303 //
1304 // -XX:VerifyArchivedFields=2 force a GC to happen in such an early stage
1305 // to check for GC safety.
1306 log_info(aot, heap)("Trigger GC %s initializing static field(s) in %s",
1307 which, k->external_name());
1308 FlagSetting fs1(VerifyBeforeGC, true);
1309 FlagSetting fs2(VerifyDuringGC, true);
1310 FlagSetting fs3(VerifyAfterGC, true);
1311 Universe::heap()->collect(GCCause::_java_lang_system_gc);
1312 }
1313 }
1314 }
1315
1316 // Before GC can execute, we must ensure that all oops reachable from HeapShared::roots()
1317 // have a valid klass. I.e., oopDesc::klass() must have already been resolved.
1318 //
1319 // Note: if a ArchivedKlassSubGraphInfoRecord contains non-early classes, and JVMTI
1320 // ClassFileLoadHook is enabled, it's possible for this class to be dynamically replaced. In
1321 // this case, we will not load the ArchivedKlassSubGraphInfoRecord and will clear its roots.
1322 void HeapShared::resolve_classes(JavaThread* current) {
1323 assert(CDSConfig::is_using_archive(), "runtime only!");
1324 if (!ArchiveHeapLoader::is_in_use()) {
1325 return; // nothing to do
1326 }
1327
1328 if (!CDSConfig::is_using_aot_linked_classes()) {
1329 assert( _run_time_special_subgraph != nullptr, "must be");
1330 Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1331 if (klasses != nullptr) {
1332 for (int i = 0; i < klasses->length(); i++) {
1333 Klass* k = klasses->at(i);
1334 ExceptionMark em(current); // no exception can happen here
1335 resolve_or_init(k, /*do_init*/false, current);
1336 }
1337 }
1338 }
1339
1340 resolve_classes_for_subgraphs(current, archive_subgraph_entry_fields);
1341 resolve_classes_for_subgraphs(current, fmg_archive_subgraph_entry_fields);
1342 }
1343
1344 void HeapShared::resolve_classes_for_subgraphs(JavaThread* current, ArchivableStaticFieldInfo fields[]) {
1345 for (int i = 0; fields[i].valid(); i++) {
1346 ArchivableStaticFieldInfo* info = &fields[i];
1347 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
1348 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name);
1349 assert(k != nullptr && k->defined_by_boot_loader(), "sanity");
1350 resolve_classes_for_subgraph_of(current, k);
1351 }
1352 }
1353
1354 void HeapShared::resolve_classes_for_subgraph_of(JavaThread* current, Klass* k) {
1355 JavaThread* THREAD = current;
1356 ExceptionMark em(THREAD);
1357 const ArchivedKlassSubGraphInfoRecord* record =
1358 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
1359 if (HAS_PENDING_EXCEPTION) {
1360 CLEAR_PENDING_EXCEPTION;
1361 }
1362 if (record == nullptr) {
1363 clear_archived_roots_of(k);
1364 }
1365 }
1366
1367 void HeapShared::initialize_java_lang_invoke(TRAPS) {
1368 if (CDSConfig::is_using_aot_linked_classes() || CDSConfig::is_dumping_method_handles()) {
1369 resolve_or_init("java/lang/invoke/Invokers$Holder", true, CHECK);
1370 resolve_or_init("java/lang/invoke/MethodHandle", true, CHECK);
1371 resolve_or_init("java/lang/invoke/MethodHandleNatives", true, CHECK);
1372 resolve_or_init("java/lang/invoke/DirectMethodHandle$Holder", true, CHECK);
1373 resolve_or_init("java/lang/invoke/DelegatingMethodHandle$Holder", true, CHECK);
1374 resolve_or_init("java/lang/invoke/LambdaForm$Holder", true, CHECK);
1375 resolve_or_init("java/lang/invoke/BoundMethodHandle$Species_L", true, CHECK);
1376 }
1377 }
1378
1379 // Initialize the InstanceKlasses of objects that are reachable from the following roots:
1380 // - interned strings
1381 // - Klass::java_mirror() -- including aot-initialized mirrors such as those of Enum klasses.
1382 // - ConstantPool::resolved_references()
1383 // - Universe::<xxx>_exception_instance()
1384 //
1385 // For example, if this enum class is initialized at AOT cache assembly time:
1386 //
1387 // enum Fruit {
1388 // APPLE, ORANGE, BANANA;
1389 // static final Set<Fruit> HAVE_SEEDS = new HashSet<>(Arrays.asList(APPLE, ORANGE));
1390 // }
1391 //
1392 // the aot-initialized mirror of Fruit has a static field that references HashSet, which
1393 // should be initialized before any Java code can access the Fruit class. Note that
1394 // HashSet itself doesn't necessary need to be an aot-initialized class.
1395 void HeapShared::init_classes_for_special_subgraph(Handle class_loader, TRAPS) {
1396 if (!ArchiveHeapLoader::is_in_use()) {
1397 return;
1398 }
1399
1400 assert( _run_time_special_subgraph != nullptr, "must be");
1401 Array<Klass*>* klasses = _run_time_special_subgraph->subgraph_object_klasses();
1402 if (klasses != nullptr) {
1403 for (int pass = 0; pass < 2; pass ++) {
1404 for (int i = 0; i < klasses->length(); i++) {
1405 Klass* k = klasses->at(i);
1406 if (k->class_loader_data() == nullptr) {
1407 // This class is not yet loaded. We will initialize it in a later phase.
1408 // For example, we have loaded only AOTLinkedClassCategory::BOOT1 classes
1409 // but k is part of AOTLinkedClassCategory::BOOT2.
1410 continue;
1411 }
1412 if (k->class_loader() == class_loader()) {
1413 if (pass == 0) {
1414 if (k->is_instance_klass()) {
1415 InstanceKlass::cast(k)->link_class(CHECK);
1416 }
1417 } else {
1418 resolve_or_init(k, /*do_init*/true, CHECK);
1419 }
1420 }
1421 }
1422 }
1423 }
1424 }
1425
1426 void HeapShared::initialize_from_archived_subgraph(JavaThread* current, Klass* k) {
1427 JavaThread* THREAD = current;
1428 if (!ArchiveHeapLoader::is_in_use()) {
1429 return; // nothing to do
1430 }
1431
1432 if (k->name()->equals("jdk/internal/module/ArchivedModuleGraph") &&
1433 !CDSConfig::is_using_optimized_module_handling() &&
1434 // archive was created with --module-path
1435 AOTClassLocationConfig::runtime()->num_module_paths() > 0) {
1436 // ArchivedModuleGraph was created with a --module-path that's different than the runtime --module-path.
1437 // Thus, it might contain references to modules that do not exist at runtime. We cannot use it.
1438 log_info(aot, heap)("Skip initializing ArchivedModuleGraph subgraph: is_using_optimized_module_handling=%s num_module_paths=%d",
1439 BOOL_TO_STR(CDSConfig::is_using_optimized_module_handling()),
1440 AOTClassLocationConfig::runtime()->num_module_paths());
1441 return;
1442 }
1443
1444 ExceptionMark em(THREAD);
1445 const ArchivedKlassSubGraphInfoRecord* record =
1446 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
1447
1448 if (HAS_PENDING_EXCEPTION) {
1449 CLEAR_PENDING_EXCEPTION;
1450 // None of the field value will be set if there was an exception when initializing the classes.
1451 // The java code will not see any of the archived objects in the
1452 // subgraphs referenced from k in this case.
1453 return;
1454 }
1455
1456 if (record != nullptr) {
1457 init_archived_fields_for(k, record);
1458 }
1459 }
1460
1461 const ArchivedKlassSubGraphInfoRecord*
1462 HeapShared::resolve_or_init_classes_for_subgraph_of(Klass* k, bool do_init, TRAPS) {
1463 assert(!CDSConfig::is_dumping_heap(), "Should not be called when dumping heap");
1464
1465 if (!k->is_shared()) {
1466 return nullptr;
1467 }
1468 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1469 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1470
1471 #ifndef PRODUCT
1472 if (_test_class_name != nullptr && k->name()->equals(_test_class_name) && record != nullptr) {
1473 _test_class = k;
1474 _test_class_record = record;
1475 }
1476 #endif
1477
1478 // Initialize from archived data. Currently this is done only
1479 // during VM initialization time. No lock is needed.
1480 if (record == nullptr) {
1481 if (log_is_enabled(Info, aot, heap)) {
1482 ResourceMark rm(THREAD);
1483 log_info(aot, heap)("subgraph %s is not recorded",
1484 k->external_name());
1485 }
1486 return nullptr;
1487 } else {
1488 if (record->is_full_module_graph() && !CDSConfig::is_using_full_module_graph()) {
1489 if (log_is_enabled(Info, aot, heap)) {
1490 ResourceMark rm(THREAD);
1491 log_info(aot, heap)("subgraph %s cannot be used because full module graph is disabled",
1492 k->external_name());
1493 }
1494 return nullptr;
1495 }
1496
1497 if (record->has_non_early_klasses() && JvmtiExport::should_post_class_file_load_hook()) {
1498 if (log_is_enabled(Info, aot, heap)) {
1499 ResourceMark rm(THREAD);
1500 log_info(aot, heap)("subgraph %s cannot be used because JVMTI ClassFileLoadHook is enabled",
1501 k->external_name());
1502 }
1503 return nullptr;
1504 }
1505
1506 if (log_is_enabled(Info, aot, heap)) {
1507 ResourceMark rm;
1508 log_info(aot, heap)("%s subgraph %s ", do_init ? "init" : "resolve", k->external_name());
1509 }
1510
1511 resolve_or_init(k, do_init, CHECK_NULL);
1512
1513 // Load/link/initialize the klasses of the objects in the subgraph.
1514 // nullptr class loader is used.
1515 Array<Klass*>* klasses = record->subgraph_object_klasses();
1516 if (klasses != nullptr) {
1517 for (int i = 0; i < klasses->length(); i++) {
1518 Klass* klass = klasses->at(i);
1519 if (!klass->is_shared()) {
1520 return nullptr;
1521 }
1522 resolve_or_init(klass, do_init, CHECK_NULL);
1523 }
1524 }
1525 }
1526
1527 return record;
1528 }
1529
1530 void HeapShared::resolve_or_init(const char* klass_name, bool do_init, TRAPS) {
1531 TempNewSymbol klass_name_sym = SymbolTable::new_symbol(klass_name);
1532 InstanceKlass* k = SystemDictionaryShared::find_builtin_class(klass_name_sym);
1533 if (k == nullptr) {
1534 return;
1535 }
1536 assert(k->defined_by_boot_loader(), "sanity");
1537 resolve_or_init(k, false, CHECK);
1538 if (do_init) {
1539 resolve_or_init(k, true, CHECK);
1540 }
1541 }
1542
1543 void HeapShared::resolve_or_init(Klass* k, bool do_init, TRAPS) {
1544 if (!do_init) {
1545 if (k->class_loader_data() == nullptr) {
1546 Klass* resolved_k = SystemDictionary::resolve_or_null(k->name(), CHECK);
1547 assert(resolved_k == k, "classes used by archived heap must not be replaced by JVMTI ClassFileLoadHook");
1548 }
1549 } else {
1550 assert(k->class_loader_data() != nullptr, "must have been resolved by HeapShared::resolve_classes");
1551 if (k->is_instance_klass()) {
1552 InstanceKlass* ik = InstanceKlass::cast(k);
1553 ik->initialize(CHECK);
1554 } else if (k->is_objArray_klass()) {
1555 ObjArrayKlass* oak = ObjArrayKlass::cast(k);
1556 oak->initialize(CHECK);
1557 }
1558 }
1559 }
1560
1561 void HeapShared::init_archived_fields_for(Klass* k, const ArchivedKlassSubGraphInfoRecord* record) {
1562 verify_the_heap(k, "before");
1563
1564 // Load the subgraph entry fields from the record and store them back to
1565 // the corresponding fields within the mirror.
1566 oop m = k->java_mirror();
1567 Array<int>* entry_field_records = record->entry_field_records();
1568 if (entry_field_records != nullptr) {
1569 int efr_len = entry_field_records->length();
1570 assert(efr_len % 2 == 0, "sanity");
1571 for (int i = 0; i < efr_len; i += 2) {
1572 int field_offset = entry_field_records->at(i);
1573 int root_index = entry_field_records->at(i+1);
1574 oop v = get_root(root_index, /*clear=*/true);
1575 if (k->has_aot_initialized_mirror()) {
1576 assert(v == m->obj_field(field_offset), "must be aot-initialized");
1577 } else {
1578 m->obj_field_put(field_offset, v);
1579 }
1580 log_debug(aot, heap)(" " PTR_FORMAT " init field @ %2d = " PTR_FORMAT, p2i(k), field_offset, p2i(v));
1581 }
1582
1583 // Done. Java code can see the archived sub-graphs referenced from k's
1584 // mirror after this point.
1585 if (log_is_enabled(Info, aot, heap)) {
1586 ResourceMark rm;
1587 log_info(aot, heap)("initialize_from_archived_subgraph %s " PTR_FORMAT "%s%s",
1588 k->external_name(), p2i(k), JvmtiExport::is_early_phase() ? " (early)" : "",
1589 k->has_aot_initialized_mirror() ? " (aot-inited)" : "");
1590 }
1591 }
1592
1593 verify_the_heap(k, "after ");
1594 }
1595
1596 void HeapShared::clear_archived_roots_of(Klass* k) {
1597 unsigned int hash = SystemDictionaryShared::hash_for_shared_dictionary_quick(k);
1598 const ArchivedKlassSubGraphInfoRecord* record = _run_time_subgraph_info_table.lookup(k, hash, 0);
1599 if (record != nullptr) {
1600 Array<int>* entry_field_records = record->entry_field_records();
1601 if (entry_field_records != nullptr) {
1602 int efr_len = entry_field_records->length();
1603 assert(efr_len % 2 == 0, "sanity");
1604 for (int i = 0; i < efr_len; i += 2) {
1605 int root_index = entry_field_records->at(i+1);
1606 clear_root(root_index);
1607 }
1608 }
1609 }
1610 }
1611
1612 // Push all oop fields (or oop array elemenets in case of an objArray) in
1613 // _referencing_obj onto the _stack.
1614 class HeapShared::OopFieldPusher: public BasicOopIterateClosure {
1615 PendingOopStack* _stack;
1616 GrowableArray<oop> _found_oop_fields;
1617 int _level;
1618 bool _record_klasses_only;
1619 KlassSubGraphInfo* _subgraph_info;
1620 oop _referencing_obj;
1621 bool _is_java_lang_ref;
1622 public:
1623 OopFieldPusher(PendingOopStack* stack,
1624 int level,
1625 bool record_klasses_only,
1626 KlassSubGraphInfo* subgraph_info,
1627 oop orig) :
1628 _stack(stack),
1629 _found_oop_fields(),
1630 _level(level),
1631 _record_klasses_only(record_klasses_only),
1632 _subgraph_info(subgraph_info),
1633 _referencing_obj(orig) {
1634 _is_java_lang_ref = AOTReferenceObjSupport::check_if_ref_obj(orig);
1635 }
1636 void do_oop(narrowOop *p) { OopFieldPusher::do_oop_work(p); }
1637 void do_oop( oop *p) { OopFieldPusher::do_oop_work(p); }
1638
1639 ~OopFieldPusher() {
1640 while (_found_oop_fields.length() > 0) {
1641 // This produces the exact same traversal order as the previous version
1642 // of OopFieldPusher that recurses on the C stack -- a depth-first search,
1643 // walking the oop fields in _referencing_obj by ascending field offsets.
1644 oop obj = _found_oop_fields.pop();
1645 _stack->push(PendingOop(obj, _referencing_obj, _level + 1));
1646 }
1647 }
1648
1649 protected:
1650 template <class T> void do_oop_work(T *p) {
1651 int field_offset = pointer_delta_as_int((char*)p, cast_from_oop<char*>(_referencing_obj));
1652 oop obj = HeapAccess<ON_UNKNOWN_OOP_REF>::oop_load_at(_referencing_obj, field_offset);
1653 if (!CompressedOops::is_null(obj)) {
1654 if (_is_java_lang_ref && AOTReferenceObjSupport::skip_field(field_offset)) {
1655 // Do not follow these fields. They will be cleared to null.
1656 return;
1657 }
1658
1659 if (!_record_klasses_only && log_is_enabled(Debug, aot, heap)) {
1660 ResourceMark rm;
1661 log_debug(aot, heap)("(%d) %s[%d] ==> " PTR_FORMAT " size %zu %s", _level,
1662 _referencing_obj->klass()->external_name(), field_offset,
1663 p2i(obj), obj->size() * HeapWordSize, obj->klass()->external_name());
1664 if (log_is_enabled(Trace, aot, heap)) {
1665 LogTarget(Trace, aot, heap) log;
1666 LogStream out(log);
1667 obj->print_on(&out);
1668 }
1669 }
1670
1671 _found_oop_fields.push(obj);
1672 }
1673 }
1674
1675 public:
1676 oop referencing_obj() { return _referencing_obj; }
1677 KlassSubGraphInfo* subgraph_info() { return _subgraph_info; }
1678 };
1679
1680 // Checks if an oop has any non-null oop fields
1681 class PointsToOopsChecker : public BasicOopIterateClosure {
1682 bool _result;
1683
1684 template <class T> void check(T *p) {
1685 _result |= (HeapAccess<>::oop_load(p) != nullptr);
1686 }
1687
1688 public:
1689 PointsToOopsChecker() : _result(false) {}
1690 void do_oop(narrowOop *p) { check(p); }
1691 void do_oop( oop *p) { check(p); }
1692 bool result() { return _result; }
1693 };
1694
1695 HeapShared::CachedOopInfo HeapShared::make_cached_oop_info(oop obj, oop referrer) {
1696 PointsToOopsChecker points_to_oops_checker;
1697 obj->oop_iterate(&points_to_oops_checker);
1698 return CachedOopInfo(OopHandle(Universe::vm_global(), referrer), points_to_oops_checker.result());
1699 }
1700
1701 void HeapShared::init_box_classes(TRAPS) {
1702 if (ArchiveHeapLoader::is_in_use()) {
1703 vmClasses::Boolean_klass()->initialize(CHECK);
1704 vmClasses::Character_klass()->initialize(CHECK);
1705 vmClasses::Float_klass()->initialize(CHECK);
1706 vmClasses::Double_klass()->initialize(CHECK);
1707 vmClasses::Byte_klass()->initialize(CHECK);
1708 vmClasses::Short_klass()->initialize(CHECK);
1709 vmClasses::Integer_klass()->initialize(CHECK);
1710 vmClasses::Long_klass()->initialize(CHECK);
1711 vmClasses::Void_klass()->initialize(CHECK);
1712 }
1713 }
1714
1715 void HeapShared::exit_on_error() {
1716 if (_context != nullptr) {
1717 ResourceMark rm;
1718 LogStream ls(Log(cds, heap)::error());
1719 ls.print_cr("Context");
1720 for (int i = 0; i < _context->length(); i++) {
1721 const char* s = _context->at(i);
1722 ls.print_cr("- %s", s);
1723 }
1724 }
1725 debug_trace();
1726 MetaspaceShared::unrecoverable_writing_error();
1727 }
1728
1729 // (1) If orig_obj has not been archived yet, archive it.
1730 // (2) If orig_obj has not been seen yet (since start_recording_subgraph() was called),
1731 // trace all objects that are reachable from it, and make sure these objects are archived.
1732 // (3) Record the klasses of all objects that are reachable from orig_obj (including those that
1733 // were already archived when this function is called)
1734 bool HeapShared::archive_reachable_objects_from(int level,
1735 KlassSubGraphInfo* subgraph_info,
1736 oop orig_obj) {
1737 assert(orig_obj != nullptr, "must be");
1738 PendingOopStack stack;
1739 stack.push(PendingOop(orig_obj, nullptr, level));
1740
1741 while (stack.length() > 0) {
1742 PendingOop po = stack.pop();
1743 _object_being_archived = po;
1744 bool status = walk_one_object(&stack, po.level(), subgraph_info, po.obj(), po.referrer());
1745 _object_being_archived = PendingOop();
1746
1747 if (!status) {
1748 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1749 // as the Java code will take care of initializing this field dynamically.
1750 assert(level == 1, "VM should have exited with unarchivable objects for _level > 1");
1751 return false;
1752 }
1753 }
1754
1755 return true;
1756 }
1757
1758 bool HeapShared::walk_one_object(PendingOopStack* stack, int level, KlassSubGraphInfo* subgraph_info,
1759 oop orig_obj, oop referrer) {
1760 assert(orig_obj != nullptr, "must be");
1761 if (!JavaClasses::is_supported_for_archiving(orig_obj)) {
1762 // This object has injected fields that cannot be supported easily, so we disallow them for now.
1763 // If you get an error here, you probably made a change in the JDK library that has added
1764 // these objects that are referenced (directly or indirectly) by static fields.
1765 ResourceMark rm;
1766 log_error(aot, heap)("Cannot archive object " PTR_FORMAT " of class %s", p2i(orig_obj), orig_obj->klass()->external_name());
1767 debug_trace();
1768 MetaspaceShared::unrecoverable_writing_error();
1769 }
1770
1771 if (log_is_enabled(Debug, aot, heap) && java_lang_Class::is_instance(orig_obj)) {
1772 ResourceMark rm;
1773 LogTarget(Debug, aot, heap) log;
1774 LogStream out(log);
1775 out.print("Found java mirror " PTR_FORMAT " ", p2i(orig_obj));
1776 Klass* k = java_lang_Class::as_Klass(orig_obj);
1777 if (k != nullptr) {
1778 out.print("%s", k->external_name());
1779 } else {
1780 out.print("primitive");
1781 }
1782 out.print_cr("; scratch mirror = " PTR_FORMAT,
1783 p2i(scratch_java_mirror(orig_obj)));
1784 }
1785
1786 if (CDSConfig::is_initing_classes_at_dump_time()) {
1787 if (java_lang_Class::is_instance(orig_obj)) {
1788 orig_obj = scratch_java_mirror(orig_obj);
1789 assert(orig_obj != nullptr, "must be archived");
1790 }
1791 } else if (java_lang_Class::is_instance(orig_obj) && subgraph_info != _dump_time_special_subgraph) {
1792 // Without CDSConfig::is_initing_classes_at_dump_time(), we only allow archived objects to
1793 // point to the mirrors of (1) j.l.Object, (2) primitive classes, and (3) box classes. These are initialized
1794 // very early by HeapShared::init_box_classes().
1795 if (orig_obj == vmClasses::Object_klass()->java_mirror()
1796 || java_lang_Class::is_primitive(orig_obj)
1797 || orig_obj == vmClasses::Boolean_klass()->java_mirror()
1798 || orig_obj == vmClasses::Character_klass()->java_mirror()
1799 || orig_obj == vmClasses::Float_klass()->java_mirror()
1800 || orig_obj == vmClasses::Double_klass()->java_mirror()
1801 || orig_obj == vmClasses::Byte_klass()->java_mirror()
1802 || orig_obj == vmClasses::Short_klass()->java_mirror()
1803 || orig_obj == vmClasses::Integer_klass()->java_mirror()
1804 || orig_obj == vmClasses::Long_klass()->java_mirror()
1805 || orig_obj == vmClasses::Void_klass()->java_mirror()) {
1806 orig_obj = scratch_java_mirror(orig_obj);
1807 assert(orig_obj != nullptr, "must be archived");
1808 } else {
1809 // If you get an error here, you probably made a change in the JDK library that has added a Class
1810 // object that is referenced (directly or indirectly) by an ArchivableStaticFieldInfo
1811 // defined at the top of this file.
1812 log_error(aot, heap)("(%d) Unknown java.lang.Class object is in the archived sub-graph", level);
1813 debug_trace();
1814 MetaspaceShared::unrecoverable_writing_error();
1815 }
1816 }
1817
1818 if (has_been_seen_during_subgraph_recording(orig_obj)) {
1819 // orig_obj has already been archived and traced. Nothing more to do.
1820 return true;
1821 } else {
1822 set_has_been_seen_during_subgraph_recording(orig_obj);
1823 }
1824
1825 bool already_archived = has_been_archived(orig_obj);
1826 bool record_klasses_only = already_archived;
1827 if (!already_archived) {
1828 ++_num_new_archived_objs;
1829 if (!archive_object(orig_obj, referrer, subgraph_info)) {
1830 // Skip archiving the sub-graph referenced from the current entry field.
1831 ResourceMark rm;
1832 log_error(aot, heap)(
1833 "Cannot archive the sub-graph referenced from %s object ("
1834 PTR_FORMAT ") size %zu, skipped.",
1835 orig_obj->klass()->external_name(), p2i(orig_obj), orig_obj->size() * HeapWordSize);
1836 if (level == 1) {
1837 // Don't archive a subgraph root that's too big. For archives static fields, that's OK
1838 // as the Java code will take care of initializing this field dynamically.
1839 return false;
1840 } else {
1841 // We don't know how to handle an object that has been archived, but some of its reachable
1842 // objects cannot be archived. Bail out for now. We might need to fix this in the future if
1843 // we have a real use case.
1844 exit_on_error();
1845 }
1846 }
1847 }
1848
1849 Klass *orig_k = orig_obj->klass();
1850 subgraph_info->add_subgraph_object_klass(orig_k);
1851
1852 {
1853 // Find all the oops that are referenced by orig_obj, push them onto the stack
1854 // so we can work on them next.
1855 ResourceMark rm;
1856 OopFieldPusher pusher(stack, level, record_klasses_only, subgraph_info, orig_obj);
1857 orig_obj->oop_iterate(&pusher);
1858 }
1859
1860 if (CDSConfig::is_initing_classes_at_dump_time()) {
1861 // The enum klasses are archived with aot-initialized mirror.
1862 // See AOTClassInitializer::can_archive_initialized_mirror().
1863 } else {
1864 if (CDSEnumKlass::is_enum_obj(orig_obj)) {
1865 CDSEnumKlass::handle_enum_obj(level + 1, subgraph_info, orig_obj);
1866 }
1867 }
1868
1869 return true;
1870 }
1871
1872 //
1873 // Start from the given static field in a java mirror and archive the
1874 // complete sub-graph of java heap objects that are reached directly
1875 // or indirectly from the starting object by following references.
1876 // Sub-graph archiving restrictions (current):
1877 //
1878 // - All classes of objects in the archived sub-graph (including the
1879 // entry class) must be boot class only.
1880 // - No java.lang.Class instance (java mirror) can be included inside
1881 // an archived sub-graph. Mirror can only be the sub-graph entry object.
1882 //
1883 // The Java heap object sub-graph archiving process (see OopFieldPusher):
1884 //
1885 // 1) Java object sub-graph archiving starts from a given static field
1886 // within a Class instance (java mirror). If the static field is a
1887 // reference field and points to a non-null java object, proceed to
1888 // the next step.
1889 //
1890 // 2) Archives the referenced java object. If an archived copy of the
1891 // current object already exists, updates the pointer in the archived
1892 // copy of the referencing object to point to the current archived object.
1893 // Otherwise, proceed to the next step.
1894 //
1895 // 3) Follows all references within the current java object and recursively
1896 // archive the sub-graph of objects starting from each reference.
1897 //
1898 // 4) Updates the pointer in the archived copy of referencing object to
1899 // point to the current archived object.
1900 //
1901 // 5) The Klass of the current java object is added to the list of Klasses
1902 // for loading and initializing before any object in the archived graph can
1903 // be accessed at runtime.
1904 //
1905 void HeapShared::archive_reachable_objects_from_static_field(InstanceKlass *k,
1906 const char* klass_name,
1907 int field_offset,
1908 const char* field_name) {
1909 assert(CDSConfig::is_dumping_heap(), "dump time only");
1910 assert(k->defined_by_boot_loader(), "must be boot class");
1911
1912 oop m = k->java_mirror();
1913
1914 KlassSubGraphInfo* subgraph_info = get_subgraph_info(k);
1915 oop f = m->obj_field(field_offset);
1916
1917 log_debug(aot, heap)("Start archiving from: %s::%s (" PTR_FORMAT ")", klass_name, field_name, p2i(f));
1918
1919 if (!CompressedOops::is_null(f)) {
1920 if (log_is_enabled(Trace, aot, heap)) {
1921 LogTarget(Trace, aot, heap) log;
1922 LogStream out(log);
1923 f->print_on(&out);
1924 }
1925
1926 bool success = archive_reachable_objects_from(1, subgraph_info, f);
1927 if (!success) {
1928 log_error(aot, heap)("Archiving failed %s::%s (some reachable objects cannot be archived)",
1929 klass_name, field_name);
1930 } else {
1931 // Note: the field value is not preserved in the archived mirror.
1932 // Record the field as a new subGraph entry point. The recorded
1933 // information is restored from the archive at runtime.
1934 subgraph_info->add_subgraph_entry_field(field_offset, f);
1935 log_info(aot, heap)("Archived field %s::%s => " PTR_FORMAT, klass_name, field_name, p2i(f));
1936 }
1937 } else {
1938 // The field contains null, we still need to record the entry point,
1939 // so it can be restored at runtime.
1940 subgraph_info->add_subgraph_entry_field(field_offset, nullptr);
1941 }
1942 }
1943
1944 #ifndef PRODUCT
1945 class VerifySharedOopClosure: public BasicOopIterateClosure {
1946 public:
1947 void do_oop(narrowOop *p) { VerifySharedOopClosure::do_oop_work(p); }
1948 void do_oop( oop *p) { VerifySharedOopClosure::do_oop_work(p); }
1949
1950 protected:
1951 template <class T> void do_oop_work(T *p) {
1952 oop obj = RawAccess<>::oop_load(p);
1953 if (!CompressedOops::is_null(obj)) {
1954 HeapShared::verify_reachable_objects_from(obj);
1955 }
1956 }
1957 };
1958
1959 void HeapShared::verify_subgraph_from_static_field(InstanceKlass* k, int field_offset) {
1960 assert(CDSConfig::is_dumping_heap(), "dump time only");
1961 assert(k->defined_by_boot_loader(), "must be boot class");
1962
1963 oop m = k->java_mirror();
1964 oop f = m->obj_field(field_offset);
1965 if (!CompressedOops::is_null(f)) {
1966 verify_subgraph_from(f);
1967 }
1968 }
1969
1970 void HeapShared::verify_subgraph_from(oop orig_obj) {
1971 if (!has_been_archived(orig_obj)) {
1972 // It's OK for the root of a subgraph to be not archived. See comments in
1973 // archive_reachable_objects_from().
1974 return;
1975 }
1976
1977 // Verify that all objects reachable from orig_obj are archived.
1978 init_seen_objects_table();
1979 verify_reachable_objects_from(orig_obj);
1980 delete_seen_objects_table();
1981 }
1982
1983 void HeapShared::verify_reachable_objects_from(oop obj) {
1984 _num_total_verifications ++;
1985 if (java_lang_Class::is_instance(obj)) {
1986 obj = scratch_java_mirror(obj);
1987 assert(obj != nullptr, "must be");
1988 }
1989 if (!has_been_seen_during_subgraph_recording(obj)) {
1990 set_has_been_seen_during_subgraph_recording(obj);
1991 assert(has_been_archived(obj), "must be");
1992 VerifySharedOopClosure walker;
1993 obj->oop_iterate(&walker);
1994 }
1995 }
1996 #endif
1997
1998 void HeapShared::check_special_subgraph_classes() {
1999 if (CDSConfig::is_initing_classes_at_dump_time()) {
2000 // We can have aot-initialized classes (such as Enums) that can reference objects
2001 // of arbitrary types. Currently, we trust the JEP 483 implementation to only
2002 // aot-initialize classes that are "safe".
2003 //
2004 // TODO: we need an automatic tool that checks the safety of aot-initialized
2005 // classes (when we extend the set of aot-initialized classes beyond JEP 483)
2006 return;
2007 } else {
2008 // In this case, the special subgraph should contain a few specific types
2009 GrowableArray<Klass*>* klasses = _dump_time_special_subgraph->subgraph_object_klasses();
2010 int num = klasses->length();
2011 for (int i = 0; i < num; i++) {
2012 Klass* subgraph_k = klasses->at(i);
2013 Symbol* name = subgraph_k->name();
2014 if (subgraph_k->is_instance_klass() &&
2015 name != vmSymbols::java_lang_Class() &&
2016 name != vmSymbols::java_lang_String() &&
2017 name != vmSymbols::java_lang_ArithmeticException() &&
2018 name != vmSymbols::java_lang_ArrayIndexOutOfBoundsException() &&
2019 name != vmSymbols::java_lang_ArrayStoreException() &&
2020 name != vmSymbols::java_lang_ClassCastException() &&
2021 name != vmSymbols::java_lang_InternalError() &&
2022 name != vmSymbols::java_lang_NullPointerException()) {
2023 ResourceMark rm;
2024 fatal("special subgraph cannot have objects of type %s", subgraph_k->external_name());
2025 }
2026 }
2027 }
2028 }
2029
2030 HeapShared::SeenObjectsTable* HeapShared::_seen_objects_table = nullptr;
2031 HeapShared::PendingOop HeapShared::_object_being_archived;
2032 int HeapShared::_num_new_walked_objs;
2033 int HeapShared::_num_new_archived_objs;
2034 int HeapShared::_num_old_recorded_klasses;
2035
2036 int HeapShared::_num_total_subgraph_recordings = 0;
2037 int HeapShared::_num_total_walked_objs = 0;
2038 int HeapShared::_num_total_archived_objs = 0;
2039 int HeapShared::_num_total_recorded_klasses = 0;
2040 int HeapShared::_num_total_verifications = 0;
2041
2042 bool HeapShared::has_been_seen_during_subgraph_recording(oop obj) {
2043 return _seen_objects_table->get(obj) != nullptr;
2044 }
2045
2046 void HeapShared::set_has_been_seen_during_subgraph_recording(oop obj) {
2047 assert(!has_been_seen_during_subgraph_recording(obj), "sanity");
2048 _seen_objects_table->put_when_absent(obj, true);
2049 _seen_objects_table->maybe_grow();
2050 ++ _num_new_walked_objs;
2051 }
2052
2053 void HeapShared::start_recording_subgraph(InstanceKlass *k, const char* class_name, bool is_full_module_graph) {
2054 log_info(aot, heap)("Start recording subgraph(s) for archived fields in %s", class_name);
2055 init_subgraph_info(k, is_full_module_graph);
2056 init_seen_objects_table();
2057 _num_new_walked_objs = 0;
2058 _num_new_archived_objs = 0;
2059 _num_old_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses();
2060 }
2061
2062 void HeapShared::done_recording_subgraph(InstanceKlass *k, const char* class_name) {
2063 int num_new_recorded_klasses = get_subgraph_info(k)->num_subgraph_object_klasses() -
2064 _num_old_recorded_klasses;
2065 log_info(aot, heap)("Done recording subgraph(s) for archived fields in %s: "
2066 "walked %d objs, archived %d new objs, recorded %d classes",
2067 class_name, _num_new_walked_objs, _num_new_archived_objs,
2068 num_new_recorded_klasses);
2069
2070 delete_seen_objects_table();
2071
2072 _num_total_subgraph_recordings ++;
2073 _num_total_walked_objs += _num_new_walked_objs;
2074 _num_total_archived_objs += _num_new_archived_objs;
2075 _num_total_recorded_klasses += num_new_recorded_klasses;
2076 }
2077
2078 class ArchivableStaticFieldFinder: public FieldClosure {
2079 InstanceKlass* _ik;
2080 Symbol* _field_name;
2081 bool _found;
2082 int _offset;
2083 public:
2084 ArchivableStaticFieldFinder(InstanceKlass* ik, Symbol* field_name) :
2085 _ik(ik), _field_name(field_name), _found(false), _offset(-1) {}
2086
2087 virtual void do_field(fieldDescriptor* fd) {
2088 if (fd->name() == _field_name) {
2089 assert(!_found, "fields can never be overloaded");
2090 if (is_reference_type(fd->field_type())) {
2091 _found = true;
2092 _offset = fd->offset();
2093 }
2094 }
2095 }
2096 bool found() { return _found; }
2097 int offset() { return _offset; }
2098 };
2099
2100 void HeapShared::init_subgraph_entry_fields(ArchivableStaticFieldInfo fields[],
2101 TRAPS) {
2102 for (int i = 0; fields[i].valid(); i++) {
2103 ArchivableStaticFieldInfo* info = &fields[i];
2104 TempNewSymbol klass_name = SymbolTable::new_symbol(info->klass_name);
2105 TempNewSymbol field_name = SymbolTable::new_symbol(info->field_name);
2106 ResourceMark rm; // for stringStream::as_string() etc.
2107
2108 #ifndef PRODUCT
2109 bool is_test_class = (ArchiveHeapTestClass != nullptr) && (strcmp(info->klass_name, ArchiveHeapTestClass) == 0);
2110 const char* test_class_name = ArchiveHeapTestClass;
2111 #else
2112 bool is_test_class = false;
2113 const char* test_class_name = ""; // avoid C++ printf checks warnings.
2114 #endif
2115
2116 if (is_test_class) {
2117 log_warning(aot)("Loading ArchiveHeapTestClass %s ...", test_class_name);
2118 }
2119
2120 Klass* k = SystemDictionary::resolve_or_fail(klass_name, true, THREAD);
2121 if (HAS_PENDING_EXCEPTION) {
2122 CLEAR_PENDING_EXCEPTION;
2123 stringStream st;
2124 st.print("Fail to initialize archive heap: %s cannot be loaded by the boot loader", info->klass_name);
2125 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2126 }
2127
2128 if (!k->is_instance_klass()) {
2129 stringStream st;
2130 st.print("Fail to initialize archive heap: %s is not an instance class", info->klass_name);
2131 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2132 }
2133
2134 InstanceKlass* ik = InstanceKlass::cast(k);
2135 assert(InstanceKlass::cast(ik)->defined_by_boot_loader(),
2136 "Only support boot classes");
2137
2138 if (is_test_class) {
2139 if (ik->module()->is_named()) {
2140 // We don't want ArchiveHeapTestClass to be abused to easily load/initialize arbitrary
2141 // core-lib classes. You need to at least append to the bootclasspath.
2142 stringStream st;
2143 st.print("ArchiveHeapTestClass %s is not in unnamed module", test_class_name);
2144 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2145 }
2146
2147 if (ik->package() != nullptr) {
2148 // This restriction makes HeapShared::is_a_test_class_in_unnamed_module() easy.
2149 stringStream st;
2150 st.print("ArchiveHeapTestClass %s is not in unnamed package", test_class_name);
2151 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2152 }
2153 } else {
2154 if (ik->module()->name() != vmSymbols::java_base()) {
2155 // We don't want to deal with cases when a module is unavailable at runtime.
2156 // FUTURE -- load from archived heap only when module graph has not changed
2157 // between dump and runtime.
2158 stringStream st;
2159 st.print("%s is not in java.base module", info->klass_name);
2160 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2161 }
2162 }
2163
2164 if (is_test_class) {
2165 log_warning(aot)("Initializing ArchiveHeapTestClass %s ...", test_class_name);
2166 }
2167 ik->initialize(CHECK);
2168
2169 ArchivableStaticFieldFinder finder(ik, field_name);
2170 ik->do_local_static_fields(&finder);
2171 if (!finder.found()) {
2172 stringStream st;
2173 st.print("Unable to find the static T_OBJECT field %s::%s", info->klass_name, info->field_name);
2174 THROW_MSG(vmSymbols::java_lang_IllegalArgumentException(), st.as_string());
2175 }
2176
2177 info->klass = ik;
2178 info->offset = finder.offset();
2179 }
2180 }
2181
2182 void HeapShared::init_subgraph_entry_fields(TRAPS) {
2183 assert(CDSConfig::is_dumping_heap(), "must be");
2184 _dump_time_subgraph_info_table = new (mtClass)DumpTimeKlassSubGraphInfoTable();
2185 init_subgraph_entry_fields(archive_subgraph_entry_fields, CHECK);
2186 if (CDSConfig::is_dumping_full_module_graph()) {
2187 init_subgraph_entry_fields(fmg_archive_subgraph_entry_fields, CHECK);
2188 }
2189 }
2190
2191 #ifndef PRODUCT
2192 void HeapShared::setup_test_class(const char* test_class_name) {
2193 ArchivableStaticFieldInfo* p = archive_subgraph_entry_fields;
2194 int num_slots = sizeof(archive_subgraph_entry_fields) / sizeof(ArchivableStaticFieldInfo);
2195 assert(p[num_slots - 2].klass_name == nullptr, "must have empty slot that's patched below");
2196 assert(p[num_slots - 1].klass_name == nullptr, "must have empty slot that marks the end of the list");
2197
2198 if (test_class_name != nullptr) {
2199 p[num_slots - 2].klass_name = test_class_name;
2200 p[num_slots - 2].field_name = ARCHIVE_TEST_FIELD_NAME;
2201 }
2202 }
2203
2204 // See if ik is one of the test classes that are pulled in by -XX:ArchiveHeapTestClass
2205 // during runtime. This may be called before the module system is initialized so
2206 // we cannot rely on InstanceKlass::module(), etc.
2207 bool HeapShared::is_a_test_class_in_unnamed_module(Klass* ik) {
2208 if (_test_class != nullptr) {
2209 if (ik == _test_class) {
2210 return true;
2211 }
2212 Array<Klass*>* klasses = _test_class_record->subgraph_object_klasses();
2213 if (klasses == nullptr) {
2214 return false;
2215 }
2216
2217 for (int i = 0; i < klasses->length(); i++) {
2218 Klass* k = klasses->at(i);
2219 if (k == ik) {
2220 Symbol* name;
2221 if (k->is_instance_klass()) {
2222 name = InstanceKlass::cast(k)->name();
2223 } else if (k->is_objArray_klass()) {
2224 Klass* bk = ObjArrayKlass::cast(k)->bottom_klass();
2225 if (!bk->is_instance_klass()) {
2226 return false;
2227 }
2228 name = bk->name();
2229 } else {
2230 return false;
2231 }
2232
2233 // See KlassSubGraphInfo::check_allowed_klass() - we only allow test classes
2234 // to be:
2235 // (A) java.base classes (which must not be in the unnamed module)
2236 // (B) test classes which must be in the unnamed package of the unnamed module.
2237 // So if we see a '/' character in the class name, it must be in (A);
2238 // otherwise it must be in (B).
2239 if (name->index_of_at(0, "/", 1) >= 0) {
2240 return false; // (A)
2241 }
2242
2243 return true; // (B)
2244 }
2245 }
2246 }
2247
2248 return false;
2249 }
2250
2251 void HeapShared::initialize_test_class_from_archive(JavaThread* current) {
2252 Klass* k = _test_class;
2253 if (k != nullptr && ArchiveHeapLoader::is_in_use()) {
2254 JavaThread* THREAD = current;
2255 ExceptionMark em(THREAD);
2256 const ArchivedKlassSubGraphInfoRecord* record =
2257 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/false, THREAD);
2258
2259 // The _test_class is in the unnamed module, so it can't call CDS.initializeFromArchive()
2260 // from its <clinit> method. So we set up its "archivedObjects" field first, before
2261 // calling its <clinit>. This is not strictly clean, but it's a convenient way to write unit
2262 // test cases (see test/hotspot/jtreg/runtime/cds/appcds/cacheObject/ArchiveHeapTestClass.java).
2263 if (record != nullptr) {
2264 init_archived_fields_for(k, record);
2265 }
2266 resolve_or_init_classes_for_subgraph_of(k, /*do_init=*/true, THREAD);
2267 }
2268 }
2269 #endif
2270
2271 void HeapShared::init_for_dumping(TRAPS) {
2272 if (CDSConfig::is_dumping_heap()) {
2273 setup_test_class(ArchiveHeapTestClass);
2274 _dumped_interned_strings = new (mtClass)DumpedInternedStrings(INITIAL_TABLE_SIZE, MAX_TABLE_SIZE);
2275 init_subgraph_entry_fields(CHECK);
2276 }
2277 }
2278
2279 void HeapShared::archive_object_subgraphs(ArchivableStaticFieldInfo fields[],
2280 bool is_full_module_graph) {
2281 _num_total_subgraph_recordings = 0;
2282 _num_total_walked_objs = 0;
2283 _num_total_archived_objs = 0;
2284 _num_total_recorded_klasses = 0;
2285 _num_total_verifications = 0;
2286
2287 // For each class X that has one or more archived fields:
2288 // [1] Dump the subgraph of each archived field
2289 // [2] Create a list of all the class of the objects that can be reached
2290 // by any of these static fields.
2291 // At runtime, these classes are initialized before X's archived fields
2292 // are restored by HeapShared::initialize_from_archived_subgraph().
2293 for (int i = 0; fields[i].valid(); ) {
2294 ArchivableStaticFieldInfo* info = &fields[i];
2295 const char* klass_name = info->klass_name;
2296 start_recording_subgraph(info->klass, klass_name, is_full_module_graph);
2297
2298 ContextMark cm(klass_name);
2299 // If you have specified consecutive fields of the same klass in
2300 // fields[], these will be archived in the same
2301 // {start_recording_subgraph ... done_recording_subgraph} pass to
2302 // save time.
2303 for (; fields[i].valid(); i++) {
2304 ArchivableStaticFieldInfo* f = &fields[i];
2305 if (f->klass_name != klass_name) {
2306 break;
2307 }
2308
2309 ContextMark cm(f->field_name);
2310 archive_reachable_objects_from_static_field(f->klass, f->klass_name,
2311 f->offset, f->field_name);
2312 }
2313 done_recording_subgraph(info->klass, klass_name);
2314 }
2315
2316 log_info(aot, heap)("Archived subgraph records = %d",
2317 _num_total_subgraph_recordings);
2318 log_info(aot, heap)(" Walked %d objects", _num_total_walked_objs);
2319 log_info(aot, heap)(" Archived %d objects", _num_total_archived_objs);
2320 log_info(aot, heap)(" Recorded %d klasses", _num_total_recorded_klasses);
2321
2322 #ifndef PRODUCT
2323 for (int i = 0; fields[i].valid(); i++) {
2324 ArchivableStaticFieldInfo* f = &fields[i];
2325 verify_subgraph_from_static_field(f->klass, f->offset);
2326 }
2327 log_info(aot, heap)(" Verified %d references", _num_total_verifications);
2328 #endif
2329 }
2330
2331 // Keep track of the contents of the archived interned string table. This table
2332 // is used only by CDSHeapVerifier.
2333 void HeapShared::add_to_dumped_interned_strings(oop string) {
2334 assert_at_safepoint(); // DumpedInternedStrings uses raw oops
2335 assert(!ArchiveHeapWriter::is_string_too_large_to_archive(string), "must be");
2336 bool created;
2337 _dumped_interned_strings->put_if_absent(string, true, &created);
2338 if (created) {
2339 // Prevent string deduplication from changing the value field to
2340 // something not in the archive.
2341 java_lang_String::set_deduplication_forbidden(string);
2342 _dumped_interned_strings->maybe_grow();
2343 }
2344 }
2345
2346 bool HeapShared::is_dumped_interned_string(oop o) {
2347 return _dumped_interned_strings->get(o) != nullptr;
2348 }
2349
2350 // These tables should be used only within the CDS safepoint, so
2351 // delete them before we exit the safepoint. Otherwise the table will
2352 // contain bad oops after a GC.
2353 void HeapShared::delete_tables_with_raw_oops() {
2354 assert(_seen_objects_table == nullptr, "should have been deleted");
2355
2356 delete _dumped_interned_strings;
2357 _dumped_interned_strings = nullptr;
2358
2359 ArchiveHeapWriter::delete_tables_with_raw_oops();
2360 }
2361
2362 void HeapShared::debug_trace() {
2363 ResourceMark rm;
2364 oop referrer = _object_being_archived.referrer();
2365 if (referrer != nullptr) {
2366 LogStream ls(Log(aot, heap)::error());
2367 ls.print_cr("Reference trace");
2368 CDSHeapVerifier::trace_to_root(&ls, referrer);
2369 }
2370 }
2371
2372 #ifndef PRODUCT
2373 // At dump-time, find the location of all the non-null oop pointers in an archived heap
2374 // region. This way we can quickly relocate all the pointers without using
2375 // BasicOopIterateClosure at runtime.
2376 class FindEmbeddedNonNullPointers: public BasicOopIterateClosure {
2377 void* _start;
2378 BitMap *_oopmap;
2379 int _num_total_oops;
2380 int _num_null_oops;
2381 public:
2382 FindEmbeddedNonNullPointers(void* start, BitMap* oopmap)
2383 : _start(start), _oopmap(oopmap), _num_total_oops(0), _num_null_oops(0) {}
2384
2385 virtual void do_oop(narrowOop* p) {
2386 assert(UseCompressedOops, "sanity");
2387 _num_total_oops ++;
2388 narrowOop v = *p;
2389 if (!CompressedOops::is_null(v)) {
2390 size_t idx = p - (narrowOop*)_start;
2391 _oopmap->set_bit(idx);
2392 } else {
2393 _num_null_oops ++;
2394 }
2395 }
2396 virtual void do_oop(oop* p) {
2397 assert(!UseCompressedOops, "sanity");
2398 _num_total_oops ++;
2399 if ((*p) != nullptr) {
2400 size_t idx = p - (oop*)_start;
2401 _oopmap->set_bit(idx);
2402 } else {
2403 _num_null_oops ++;
2404 }
2405 }
2406 int num_total_oops() const { return _num_total_oops; }
2407 int num_null_oops() const { return _num_null_oops; }
2408 };
2409 #endif
2410
2411 void HeapShared::count_allocation(size_t size) {
2412 _total_obj_count ++;
2413 _total_obj_size += size;
2414 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2415 if (size <= (size_t(1) << i)) {
2416 _alloc_count[i] ++;
2417 _alloc_size[i] += size;
2418 return;
2419 }
2420 }
2421 }
2422
2423 static double avg_size(size_t size, size_t count) {
2424 double avg = 0;
2425 if (count > 0) {
2426 avg = double(size * HeapWordSize) / double(count);
2427 }
2428 return avg;
2429 }
2430
2431 void HeapShared::print_stats() {
2432 size_t huge_count = _total_obj_count;
2433 size_t huge_size = _total_obj_size;
2434
2435 for (int i = 0; i < ALLOC_STAT_SLOTS; i++) {
2436 size_t byte_size_limit = (size_t(1) << i) * HeapWordSize;
2437 size_t count = _alloc_count[i];
2438 size_t size = _alloc_size[i];
2439 log_info(aot, heap)("%8zu objects are <= %-6zu"
2440 " bytes (total %8zu bytes, avg %8.1f bytes)",
2441 count, byte_size_limit, size * HeapWordSize, avg_size(size, count));
2442 huge_count -= count;
2443 huge_size -= size;
2444 }
2445
2446 log_info(aot, heap)("%8zu huge objects (total %8zu bytes"
2447 ", avg %8.1f bytes)",
2448 huge_count, huge_size * HeapWordSize,
2449 avg_size(huge_size, huge_count));
2450 log_info(aot, heap)("%8zu total objects (total %8zu bytes"
2451 ", avg %8.1f bytes)",
2452 _total_obj_count, _total_obj_size * HeapWordSize,
2453 avg_size(_total_obj_size, _total_obj_count));
2454 }
2455
2456 bool HeapShared::is_archived_boot_layer_available(JavaThread* current) {
2457 TempNewSymbol klass_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_CLASS);
2458 InstanceKlass* k = SystemDictionary::find_instance_klass(current, klass_name, Handle());
2459 if (k == nullptr) {
2460 return false;
2461 } else {
2462 TempNewSymbol field_name = SymbolTable::new_symbol(ARCHIVED_BOOT_LAYER_FIELD);
2463 TempNewSymbol field_signature = SymbolTable::new_symbol("Ljdk/internal/module/ArchivedBootLayer;");
2464 fieldDescriptor fd;
2465 if (k->find_field(field_name, field_signature, true, &fd) != nullptr) {
2466 oop m = k->java_mirror();
2467 oop f = m->obj_field(fd.offset());
2468 if (CompressedOops::is_null(f)) {
2469 return false;
2470 }
2471 } else {
2472 return false;
2473 }
2474 }
2475 return true;
2476 }
2477
2478 #endif // INCLUDE_CDS_JAVA_HEAP